Wikipedia:Citing sources

Welcome to our website. It is generaly simplier version of wikipedia. You will find there selected articles. Enjoy!

For a simple introduction to citing sources, see Wikipedia:Referencing for beginners.

This page documents an English Wikipedia content guideline. It is a generally accepted standard that editors should attempt to follow, though it is best treated with common sense, and occasional exceptions may apply. Any substantive edit to this page should reflect consensus. When in doubt, discuss first on the talk page.

Shortcuts: WP:CITE WP:REF

A citation, or reference, is a line of text that uniquely identifies a source:

Ritter, Ron. The Oxford Style Manual. Oxford University Press, 2002, p. 1.

Citations are an important part of any Wikipedia article, serving to identify the reliable sources on which the article is based. In most cases, citations for specific pieces of information contained in an article are given in the form of footnotes, though they can also appear within the body of an article. Citations indicated by a superscript number or other means in a line of text are called inline citations.

Wikipedia's Verifiability policy requires inline citations for any material challenged or likely to be challenged, and for all quotations, anywhere in article space. However, editors are advised to provide citations for all material added to Wikipedia; any detail risks being unexpectedly challenged or even eventually removed.

This page contains information on how to place and format citations. Each article should use the same citation method throughout. If an article already has citations, adopt the method in use or seek consensus on the talk page before changing it. While you should try to write citations correctly, what matters most is that you provide enough information to identify the source. Others will improve the formatting if needed.

Wikipedia guidelines
Behavioral
Assume good faith Conflict of interest Don't bite the newbies Don't disrupt Wikipedia to make a point Etiquette Gaming the system User pages
Content
Citing sources Identifying reliable sources
Stand-alone article
Notability
Discussion
Signatures Talk page guidelines
Editing
Article size Be bold Don't add the full text of primary sources Don't create hoaxes Edit summary Patent nonsense
Organization
Categories, lists, and templates Categorization Disambiguation Subpages
Style
Manual of Style Manual of Style/Lists Manual of Style/Tables
More
List of policies and guidelines

1 Types of citation
2 When and why to cite sources
3 Inline citations
- 3.1 Footnotes
- 3.2 Parenthetical referencing
4 General references
5 What information to include
6 Citation style
- 6.1 Variation in citation methods
7 Handling links in citations
8 Text-source integrity
9 Bundling citations
10 In-text attribution
11 Dealing with unsourced material
12 Citation templates and tools
13 See also
14 Notes
15 Further reading

Types of citation

A full citation fully identifies a reliable source and, where applicable, the place in that source (such as a page number) where the information in question can be found. For example: Rawls, John. A Theory of Justice. Harvard University Press, 1971, p. 1. This type of citation is usually given as a footnote, and is the most commonly used citation method in Wikipedia articles.

An inline citation means any citation added close to the material it supports, for example after the sentence or paragraph, normally in the form of a footnote.

A general reference is a citation to a reliable source that supports content, but is not displayed as an inline citation. General references are usually listed at the end of the article in a References section. They may be found in underdeveloped articles, especially when all article content is supported by a single source. They may also be listed by author alphabetically in a References section in more developed articles as a supplement to inline citations.

A short citation is an inline citation that identifies the place in a source where specific information can be found, but without giving full details of the source – these will have been provided in a general reference. For example: Rawls 1971, p. 1. This system is used in some articles; the short citations may be given either as footnotes, or as parenthetical references within the text.

In-text attribution means saying within the article text itself (not as a mere footnote) where particular statements come from. This is done especially with statements of opinion, uncertain facts, and quotations. Usually the in-text attribution does not specify full details of the source text – this is done with a footnote in the normal way. For example: According to John Rawls,^[5]... See In-text attribution below.

When and why to cite sources

By citing sources for Wikipedia content, you enable other editors and readers to verify that the information given is supported by reliable sources, thus improving the credibility of Wikipedia and showing that the material is not original research. You also help readers find additional information on the subject; and you avoid committing plagiarism (by giving credit to the source of your words or ideas).

In particular, sources are required for material that is challenged or likely to be challenged – if reliable sources cannot be found for challenged material, it is likely to be removed from the article. Sources are also required when quoting someone, with or without quotation marks, or closely paraphasing a source. However, the citing of sources is not limited to those situations – editors are always encouraged to add or improve citations for any information contained in an article.

Citations are especially desirable for statements about living persons, particularly when the statements are contentious or potentially defamatory. In accordance with the biography of living persons policy, unsourced information of this type is likely to be removed on sight.

Citations are not used on disambiguation pages (sourcing for the information given there should be done in the target articles). Citations are also often discouraged in the lead section of an article, insofar as it summarizes information for which sources are given later in the article, although such things as quotations and particularly controversial statements should be supported by citations even in the lead.

For an image or other media file, details of its origin and copyright status should appear on its file page. Image captions should be referenced as appropriate just like any other part of the article. A citation is not needed for descriptions such as alt text that are verifiable directly from the image itself, or for text that merely identifies a source (e.g., the caption "Belshazzar's Feast (1635)" for File:Rembrandt-Belsazar.jpg).

Inline citations

Shortcut: WP:INCITE

Further information: Wikipedia:Inline citation

Inline citations allow the reader to associate a given bit of material in an article with the specific reliable source(s) that support the material. Inline citations are most commonly added using either footnotes (long or short) or parenthetical references. This section describes how to add either type, and also describes how to create a list of full bibliography citations to support shortened footnotes or parenthetical references.

Footnotes

How to place an inline citation using ref tags

Shortcut: WP:CITEFOOT

To create a footnote, use the <ref>...</ref> syntax at the appropriate place in the article text, for example:

Justice is a human invention.<ref>Rawls, John. ''A Theory of Justice''. Harvard University Press, 1971, p. 1.</ref> It...

which will be displayed as something like:

Justice is a human invention. It...

It will also be necessary to generate the list of footnotes (where the citation text is actually displayed); for this, see the next section.

As in the above example, citation markers are normally placed after adjacent punctuation such as periods and commas. For exceptions, see the Punctuation and footnotes section of the Manual of Style. Note also that no space is added before the citation marker.

The citation should be added close to the material it supports, offering text-source integrity. If a word or phrase is particularly contentious, an inline citation may be added next to that word or phrase within the sentence, but it is usually sufficient to add the citation to the end of the sentence or paragraph, so long as it's clear which source supports which part of the text. If an infobox or table contains text that needs citing, but the box or table cannot incorporate an inline citation, the citation should appear in a caption or other text that discusses the material.

How to create the list of citations

The first editor to add footnotes to an article must create a section where the text of those citations appears. This section is placed at or near the bottom of the article and is usually titled "Notes" or "References." For more about the order and titles of sections at the end of an article (which may also include "Further reading" and "External links" sections), see Wikipedia:Footers.

Shortcut: WP:ASL

With some exceptions discussed below, citations appear in a single section containing only the <references /> tag or the {{reflist}} template. For example:

==Notes==

{{reflist}}

The footnotes will then automatically be listed under that section heading. Each numbered footnote marker in the text is a clickable link to the corresponding footnote, and each footnote contains a caret which links back to the corresponding point in the text. Scrolling lists, or lists of citations appearing within a scroll box, should never be used. This is because of issues with readability, browser compatibility, accessibility, printing, and site mirroring.

If an article contains a list of general references, this is placed in a separate section, titled (for example) "References". This usually comes immediately after the section(s) listing footnotes, if any. (If the general references section is called "References", then the citations section is usually called "Notes".)

Separating citations from explanatory footnotes

If an article contains both footnoted citations and other (explanatory) footnotes, then it is possible (but not necessary) to divide them into two separate lists, using the grouping feature described in the Grouping footnotes section of the footnotes help page. The explanatory footnotes and the citations are then placed in separate sections, called (for example) "Notes" and "References" respectively.

Repeated citations

For multiple use of the same citation or footnote, you can also use the named references feature, choosing a name to identify the citation, and typing <ref name="name">text of the citation</ref>. Thereafter, the same footnote may be reused any number of times by typing just <ref name="name" />. For more details of this syntax, see Multiple references to the same footnote on the footnotes help page.

Avoiding clutter

Inline references can significantly bloat the wikitext in the edit window and can be extremely difficult and confusing. There are three methods that avoid clutter in the edit window: list-defined references, short citations or parenthetical references. (As with other citation formats, articles should not undergo large scale conversion between formats without consensus to do so.)

Citing multiple pages of the same source

When an article cites many different pages from the same source, most Wikipedia editors use short citations in footnotes. Other methods include short citations in parenthesis and the template {{rp}}.

Shortcut: WP:IBID

The use of ibid., Id. (or similar abbreviations) is discouraged, as these may become broken as new references are added (op. cit. is less problematic in that it should refer explicitly to a citation contained in the article; however, not all readers are familiar with the meaning of the terms). If the use of ibid is extensive, use the {{ibid}} template.

Short citations

Shortcuts: WP:CITESHORT WP:SFN

Main page: Help:Shortened footnotes

Some Wikipedia articles use short citations, giving summary information about the source together with a page number, as in <ref>Smith 2010, p. 1.</ref>. These are used together with general references, which give full details of the sources, but without page numbers, and are listed in a separate "References" section. Short citations are used in articles which apply parenthetical referencing (see below), but they can also be used as footnote citations, as described here.

Forms of short citations used include author-date referencing (APA style, Harvard style, or Chicago style), and author-title or author-page referencing (MLA style or Chicago style). As before, the list of footnotes is automatically generated in a "Notes" or "Footnotes" section, which immediately precedes the "References" section containing the general references. Short citations can be written manually, or by using the {{sfn}} or {{harvnb}} templates. (Note that templates should not be added without consensus to an article that already uses a consistent referencing style.) The short citations and general references may be linked so that the reader can click on the short note to find full information about the source. See the template documentation for details and solutions to common problems. For variations with and without templates, see wikilinks to full references. For a set of realistic examples, see these.

This is how short citations look in the edit box:

The Sun is pretty big,<ref>Miller 2005, p. 23.</ref> but the Moon is not so big.<ref>Brown 2006, p. 46.</ref> The Sun is also quite hot.<ref>Miller 2005, p. 34.</ref> == Notes == {{Reflist}} == References == *Brown, Rebecca (2006). "Size of the Moon," ''Scientific American'', 51(78). *Miller, Edward (2005). ''The Sun''. Academic Press.

This is how they look in the article:

The Sun is pretty big, but the Moon is not so big. The Sun is also quite hot.

Notes

^ Miller 2005, p. 23.

^ Brown 2006, p. 46.

^ Miller 2005, p. 34.

References

Brown, Rebecca (2006). "Size of the Moon", Scientific American, 51(78).

Miller, Edward (2005). The Sun. Academic Press.

Shortened notes using titles rather than publication dates would look like this in the article:

Notes

^ Miller, The Sun, p. 23.

^ Brown, "Size of the Moon", p. 46.

^ Miller, The Sun, p. 34.

When using manual links it is easy to introduce errors such as duplicate anchors and unused references. The script User:Ucucha/HarvErrors will show many related errors. Duplicate anchors may be found by using the W3C Markup Validation Service.

Parenthetical referencing

Further information: Wikipedia:Parenthetical referencing

While most articles use footnote citations as described in the above sections, some articles use a parenthetical referencing style. Here, short citations in parentheses, such as (Smith 2010, p. 1), are placed within the article text itself. Full details of each source used are given in a general reference, e.g. Smith, John. Name of Book. Cambridge University Press, 2010. The general references are listed in alphabetical order, according to the authors' surnames, at the end of the article in a "References" section.

Several forms of short citation are used in Wikipedia; see Short citations above. The inline citation and general reference may be linked using a template (see linking inline and full citations); as with other citation templates, these should not be added to articles without consensus.

This is how it looks in the edit box:

The Sun is pretty big (Miller 2005, p. 1), but the Moon is not so big (Brown 2006, p. 2). The Sun is also quite hot (Miller 2005, p. 3). == References == *Brown, R (2006). "Size of the Moon", ''Scientific American'', 51(78). *Miller, E (2005). ''The Sun'', Academic Press.

This is how it looks in the article:

The Sun is pretty big (Miller 2005, p. 1), but the Moon is not so big (Brown 2006, p. 2). The Sun is also quite hot (Miller 2005, p. 3).

References

Brown, R (2006). "Size of the Moon", Scientific American, 51(78).

Miller, E (2005). The Sun, Academic Press.

Notice that, unlike footnotes, parenthetical references are placed before adjacent punctuation such as commas and full stops.

General references

Shortcut: WP:GENREF

A general reference is a citation to a reliable source that supports content, but is not displayed as an inline citation. General references are usually listed at the end of the article in a "References" section, and are usually sorted by the last name of the author or the editor. Examples of general reference sections are given above, in the sections on short citations and parenthetical references.

In addition to their use when short or parenthetical references are used, a general references section may also be included in an article that uses full inline citations, particularly if such citations have not yet been given for all the information in the article. In underdeveloped articles, a general references section may exist even though no inline citations at all have yet been added, especially when all article content is supported by a single source. The disadvantage of using general references alone is that text-source integrity is lost, unless the article is very short.

What information to include

Shortcut: WP:CITEHOW

Listed below is the information which a typical inline citation or general reference will provide, in order to identify the source, assist readers in finding it, and (in the case of inline citations) indicate the place in the source where the information is to be found. (If an article uses parenthetical referencing or short citations, then the inline citations will refer to this information in abbreviated form, as described in the relevant sections above.)

Examples

Books

Citations for books typically include:

name of the author(s)
title of the book in italics
volume when appropriate
city of publication is optional
name of the publisher
year of publication
chapter or page number(s) where appropriate
ISBN where available

Citations for individually authored chapters in books typically include:

name of author
the title of the chapter
name of the book's editor
name of book and other details as above
the chapter number or page numbers for the chapter are optional

Journal articles

Citations for journal articles typically include:

name of the author(s)
year and sometimes month of publication
title of the article within quotation marks
name of the journal in italics
volume number, issue number, and page numbers (article numbers in some electronic journals)
DOI and/or other identifiers where available

Newspaper articles

Citations for newspaper articles typically include:

name of the newspaper in italics
date of publication
byline (author's name), if any
title of the article within quotation marks
city of publication, if not included in name of newspaper
page number(s) are optional

Webpages

Citations for World Wide Web pages typically include:

name of the author(s)
title of the article within quotation marks
name of the website
date of publication
page number(s) (if applicable)
the date you retrieved it (required if the publication date is unknown)

Sound recordings

Citations for sound recordings typically include:

name of the composer(s)/songwriter(s)/script writer(s)
name of the performer(s)
title of the song or individual track in quotation marks
title of the album in italics (if applicable)
name of the record label
year of release
medium (for example: LP, audio cassette, CD, MP3 file)
approximate time at which event or point of interest occurs, where appropriate

Film, TV, or video recordings

Citations for films, TV episodes, or video recordings typically include:

name of the director
name of the producer, if relevant
names of major performers
for a TV episode, the title of the episode in quotation marks
title of the film or TV series in italics
name of the studio
year of release
medium (for example: film, videocassette, DVD)
approximate time at which event or point of interest occurs, where appropriate

Identifying parts of a source

Shortcut: WP:Page numbers

When citing lengthy sources, you should identify which part of a source is being cited.

Books and print articles

Specify the page number or range of page numbers. Page numbers are not required for a reference to the book or article as a whole. When you specify a page number, it is helpful to specify the version (date and edition for books) of the source because the layout, pagination, length, etc. can change between editions.

Audio and video sources

Specify the time at which the event or other point of interest occurs. Be as precise as possible about the version of the source that you are citing; for example, movies are often released in different editions or "cuts". Due to variations between formats and playback equipment, precision may not be accurate in some cases. However, many government agencies do not publish minutes and transcripts but do post video of official meetings online; generally the subcontractors who handle audio-visual are quite precise.

Links and ID numbers

A citation ideally includes a link or ID number to help editors locate the source. If you have a URL (webpage) link, you can add it to the title part of the citation, so that when you add the citation to Wikipedia the URL becomes hidden and the title becomes clickable. To do this, enclose the URL and the title in square brackets—the URL first, then a space, then the title. For example:

Carr A, Ory D (2006). [http://dx.doi.org/10.1371/journal.pmed.0030496 Does HIV cause cardiovascular disease?] ''PLoS Medicine'', 3(11):e496.

For web-only sources with no publication date you should include a "Retrieved" date instead, in case the webpage changes in the future. For example: Retrieved 2008-07-15.

You can also add an ID number to the end of a citation. The ID number might be an ISBN for a book, a DOI (Digital Object Identifier) for an article, or any of several ID numbers that are specific to particular article databases, such as a PMID number for articles on PubMed. It may be possible to format these so that they are automatically activated and become clickable when added to Wikipedia, for example by typing ISBN (or PMID) following by a space followed by the ID number.

If your source is not available online, it should be available in reputable libraries, archives, or collections. If a citation without an external link is challenged as unavailable, any of the following is sufficient to show the material to be reasonably available (though not necessarily reliable): providing an ISBN or OCLC number; linking to an established Wikipedia article about the source (the work, its author, or its publisher); or directly quoting the material on the talk page, briefly and in context.

Linking to Google Books pages

Shortcuts: WP:PAGELINK WP:PAGELINKS

Further information: Wikipedia talk:Citing sources/Archive 29#Linking to Google Books pages

Google Books allows book pages to be linked to directly, where the book is available for preview. These can be written in a number of ways, with or without citation templates:

Rawls, John. A Theory of Justice. Harvard University Press, 1971, p. 18.
Rawls 1971, p. 18.
Rawls 1971, p. 18.
Rawls 1971, p. 18.

In edit mode, the URL for p. 18 of A Theory of Justice looks like this:

Rawls, John. [http://books.google.com/books?id=kvpby7HtAe0C&pg=PA18 ''A Theory of Justice'']. Harvard University Press, 1971, p. 18.

When the page number is a Roman numeral, commonly seen at the beginning of books, the URL looks like this:

http://books.google.com/books?id=kvpby7HtAe0C&pg=PR17—for page xvii of the same book.

Page links should only be added when the book is available for preview; they will not work with snippet view. No editor is required to add page links, but if another editor adds them, they should not be removed; see the October 2010 RfC for further information.

Convenience links

Main page: Wikipedia:Copyrights#Linking to copyrighted works

A convenience link is a link to a copy of your source on a webpage provided by someone other than the original publisher or author. For example, a copy of a newspaper article no longer available on the newspaper's website may be hosted elsewhere. When offering convenience links, it is important to be reasonably certain that the convenience copy is a true copy of the original, without any changes or inappropriate commentary, and that it does not infringe the original publisher's copyright. Accuracy can be assumed when the hosting website appears reliable. Where several sites host a copy of the material, the site selected as the convenience link should be the one whose general content appears most in line with Wikipedia:Neutral point of view and Wikipedia:Verifiability.

Citation style

While citations should aim to provide the information listed above, Wikipedia does not have a single house style, though citations within any given article should follow a consistent style. A number of citation styles exist (some relevant Wikipedia articles include Citation, APA style, MLA style, The Chicago Manual of Style, Author-date referencing, Vancouver system and Bluebook). Examples can be found at Wikipedia:Citing sources/Example style.

Although nearly any consistent style may be used, avoid all-numeric date formats other than YYYY-MM-DD, because of the ambiguity concerning which number is the month and which the day. For example, 2002-06-11 may be used, but not 11/06/2002. The YYYY-MM-DD format should in any case be limited to Gregorian calendar dates where the year is after 1582.

Variation in citation methods

Shortcut: WP:CITEVAR

Editors should not attempt to change an article's established citation style merely on the grounds of personal preference, or without first seeking consensus for the change. If the article you are editing is already using a particular citation style, you should follow it; if you believe it is inappropriate for the needs of the article, seek consensus for a change on the talk page. As with spelling differences, if there is disagreement about which style is best, defer to the style used by the first major contributor. If you are the first contributor to add citations to an article, you may choose whichever style you think best for the article.

To be avoided

Switching between major citation styles, e.g., switching between parenthetical and <ref> tags or between the style preferred by one academic discipline vs. another
Adding citation templates to an article that already uses a consistent system without templates, or removing citation templates from an article that uses them consistently

Generally considered helpful

Improving existing citations by adding missing information; for example, replacing bare URLs with full bibliographic citations: an improvement because it fights linkrot
Replacing some or all general references with inline citations: an improvement because it provides more information to the reader and helps maintain text-source integrity
Imposing one style on an article with incompatible citation styles (e.g., some of the citations in footnotes and others as parenthetical references): an improvement because it makes the formatting consistent

Handling links in citations

As noted above under What information to include, it is helpful to include hyperlinks to source material, when available. Here we note some issues concerning these links.

Avoid embedded links

Further information: Wikipedia:Embedded citations

Embedded links to external websites should not be used as a form of inline citation, because they are highly susceptible to linkrot. Wikipedia allowed this in its early years—for example by adding a link after a sentence, like this [http://media.guardian.co.uk/site/story/0,14173,1601858,00.html], which looks like this. [1] This is no longer recommended. Raw links are not recommended in lieu of properly written out citations, even if placed between ref tags, like this <ref>[http://media.guardian.co.uk/site/story/0,14173,1601858,00.html]</ref>.

Embedded links should never be used to place external links in the body of an article, like this: "Apple, Inc. announced their latest product..."

Convenience links

Main page: Wikipedia:Copyrights#Linking to copyrighted works

Indicating availability

Links to sources

For a source available in hardcopy, microform, and/or online, omit, in most cases, which one you read. While it is useful to cite author, title, edition (1st, 2nd, etc.), and similar information, it generally is not important to cite a database such as ProQuest, EbscoHost, or JStor (see the list of academic databases and search engines) or to link to such a database requiring a subscription or a third party's login. The basic bibliographic information you provide should be enough to search for the source in any of these databases that have the source. Don't add a URL that has a part of a password embedded in the URL. However, you may provide the DOI, ISBN, or another uniform identifier, if available. If the publisher offers a link to the source or its abstract that does not require a payment or a third party's login for access, you may provide the URL for that link. And if the source only exists online, give the link even if access is restricted.

Preventing and repairing dead links

Text-source integrity

Shortcut: WP:INTEGRITY

When using inline citations, it is important to maintain text-source integrity. The point of an inline citation is to allow readers and other editors to check that the material is sourced; that point is lost if the citation is not clearly placed. The distance between material and its source is a matter of editorial judgment, but adding text without placing its source clearly can lead to allegations of original research, violations of the sourcing policy, and even plagiarism. Editors should exercise caution when rearranging or inserting material to ensure that text-source relationships are maintained.

When new text is inserted into a paragraph make sure that it is clear what facts the inline citations support. For example

The sun is pretty big. The sun is also quite hot.

Notes

^ Miller, Edward. The Sun. Academic Press, 2005, p. 1.

^ Smith, John. The Sun's Heat. Academic Press, 2005, p. 2.

Do not add facts into a fully cited paragraph or sentence

N The sun is pretty big, but the moon is not so big. The sun is also quite hot.

Notes

^ Miller, Edward. The Sun. Academic Press, 2005, p. 1.

^ Smith, John. The Sun's Heat. Academic Press, 2005, p. 2.

without including a source to cover the new information.

Y The sun is pretty big, but the moon is not so big. The sun is also quite hot.

Notes

^ Miller, Edward. The Sun. Academic Press, 2005, p. 1.

^ Brown, Rebecca. "Size of the Moon," Scientific American, 51(78):46.

^ Smith, John. The Sun's Heat. Academic Press, 2005, p. 2.

Including too many citations within a sentence may be aesthetically unpleasant:

The sun is the closest star to the planet Earth, but the moon is even closer.

So consider placing them at a more aesthetically pleasant location:

The sun is the closest star to the planet Earth, but the moon is even closer.

However this solution brings its own problems:

A string of independent citations can also appear aesthetically unpleasant so consider bundling them into one.
Identifying which inline citation supports which fact can be more difficult unless additional information is added to the inline citations to explicitly identify what portion of the sentence they cover.
Maintenance becomes more difficult. When adding more information to the sentence from yet another source it may be difficult to work out precisely where to place the new citation. If the text is rearranged during a copy edit greater care needs to be taken with rearranging the citations, particularly as the inline citations will be renumbered during their repositioning.

For example if the sentence

The sun is the closest star to the planet Earth, but the moon is even closer.

is rearranged like this:

The moon is closer to planet Earth than the nearest star which is called the sun.

It will be fairly easy to check that the citations support the information in the rearranged sentence. This rearrangement is more difficult to check:

The sun is the closest star to the planet Earth, but the moon is even closer.

The moon is closer to planet Earth than the nearest star which is called the sun.

Bundling citations

Shortcuts: WP:CITEBUNDLE WP:BUNDLING

Further information: Wikipedia:Citation overkill

Sometimes the article is more readable if multiple citations are bundled into a single footnote. For example, when there are multiple sources for a given sentence, and each source applies to the entire sentence, the sources can be placed at the end of the sentence, like this. Or they can be bundled into one footnote at the end of the sentence or paragraph, like this.

Bundling is useful if the sources each support a different portion of the preceding text, or if the sources all support the same text. Bundling has several advantages:

It helps readers and other editors see at a glance which source supports which point, maintaining text-source integrity;
It avoids the visual clutter of multiple clickable footnotes inside a sentence or paragraph;
It avoids the confusion of having multiple sources listed separately after sentences, with no indication of which source to check for each part of the text, such as this.
It makes it less likely that inline citations will be moved inadvertently when text is re-arranged, because the footnote states clearly which source supports which point.

When formatting multiple citations in a footnote, there are several layouts available, as illustrated below. Within a given article, only a single layout should be used.

The sun is pretty big, but the moon is not so big. The sun is also quite hot.

Notes

Bullets

^ For the sun's size, see Miller, Edward. The Sun. Academic Press, 2005, p. 1.

For the moon's size, see Brown, Rebecca. "Size of the Moon," Scientific American, 51(78):46.

For the sun's heat, see Smith, John. The Sun's Heat. Academic Press, 2005, p. 2.

Line breaks

^ For the sun's size, see Miller, Edward. The Sun. Academic Press, 2005, p. 1.
For the moon's size, see Brown, Rebecca. "Size of the Moon," Scientific American, 51(78):46.
For the sun's heat, see Smith, John. The Sun's Heat. Academic Press, 2005, p. 2.
Paragraph

^ For the sun's size, see Miller, Edward. The Sun. Academic Press, 2005, p. 1. For the moon's size, see Brown, Rebecca. "Size of the Moon," Scientific American, 51(78):46. For the sun's heat, see Smith, John. The Sun's Heat. Academic Press, 2005, p. 2.

In-text attribution

Shortcut: WP:INTEXT

In-text attribution is the attribution inside a sentence of material to its source, in addition to an inline citation after the sentence. In-text attribution should be used with direct speech (a source's words between quotation marks); indirect speech (a source's words without quotation marks); and close paraphrasing. It can also be used when loosely summarizing a source's position in your own words. It avoids inadvertent plagiarism, and helps the reader see where a position is coming from. An inline citation should follow the attribution, usually at the end of the sentence or paragraph in question.

For example:

Y John Rawls argues that, to reach fair decisions, parties must consider matters as if behind a veil of ignorance.

When using in-text attribution, make sure it doesn't lead to an inadvertent neutrality violation. For example, the following implies parity between the sources, without making clear that the position of Dawkins is the majority view:

N Richard Dawkins argues that human beings evolved through natural selection, but John Smith writes that we arrived here in pods from Mars.

Neutrality issues apart, there are other ways in-text attribution can mislead. The sentence below suggests The New York Times has alone made this important discovery:

N According to The New York Times, the sun will set in the west this evening.

Simple facts such as this can have inline citations to reliable sources as an aid to the reader, but normally the text itself is best left as a plain statement without in-text attribution:

YBy mass, oxygen is the third most abundant element in the universe after hydrogen and helium.

Dealing with unsourced material

Shortcut: WP:NOCITE

If an article is unreferenced, you can tag it with the {{unreferenced}} template, so long as it is not nonsensical or a biography of a living person, in which case request admin assistance.

If a claim is doubtful but not harmful, use the {{citation needed}} template, which will add an inline tag, but remember to go back and remove the claim if no source is produced within a reasonable time.
If a claim is doubtful and harmful, remove it from the article. You may want to move it to the talk page and ask for a source, unless it is very harmful or absurd, in which case it should not be posted to the talk page either. Use your common sense.
All unsourced and poorly sourced contentious material about living persons must be removed from articles and talk pages immediately. See Wikipedia:Biographies of living persons and Wikipedia:Libel.

Citation templates and tools

Further information: Wikipedia:Citation templates and Wikipedia:Citation tools

For a comparison of citations using templates with citations written freehand, see Wikipedia:Citing sources/Example edits for different methods.

Citation templates can be used to format citations in a consistent way. The use of citation templates is neither encouraged nor discouraged: an article should not be switched between templated and non-templated citations without good reason and consensus – see Variation in citation methods above.

If citation templates are used in an article, the parameters should be accurate. It is inappropriate to set parameters to false values in order that the template will be rendered to the reader as if it were written in some style other than the style normally produced the template (e.g. MLA style).

Metadata

Citations may be accompanied by metadata, though it is not mandatory. Most citation templates on Wikipedia use the COinS standard. Metadata such as this allow browser plugins and other automated software to make citation data accessible to the user, for instance by providing links to their library's online copies of the cited works. In articles that format citations manually, metadata may be added manually in a span, according to the COinS specification.

Citation processing tools

Citation template generator – generates completed templates using identifying numbers such PMIDs (PubMed IDs).
Template:Citation/core – a core template used by other citation templates
User:Citation bot (formerly DOI bot) – a bot that automatically fixes common errors in individual citations, and adds missing fields
User:CitationTool – a tool for finding article-level citation errors and fixing them. Not currently functional.
Wikipedia citation tool for Google Books – converts bare Google book links into {{cite book}} format.
DOI Wikipedia reference generator
New York Times Wikipedia reference generator
Reflinks adds titles to bare references and other cleanup

Programming tools

Wikicite is a free program that helps editors to create citations for their Wikipedia contributions using citation templates. It is written in Visual Basic .NET, making it suitable only for users with the .NET Framework installed on Windows, or, for other platforms, the Mono alternative framework. Wikicite and its source code is freely available; see the developer's page for further details.
- Wikicite+ is a program based on the original Wikicite source code. It features extra validation, bug fixes, additional cite templates (such as cite episode) as well as tools for stub sorting and more. It is also available for free under the Apache License 2.0 and is open source.
User:Richiez has tools to automatically handle citations for a whole article at a time. Converts occurrences of {{pmid XXXX}} or {{isbn XXXX}} to properly formatted footnote or Harvard-style references. Written in ruby and requires a working installation with basic libraries.
pubmed2wiki.xsl an XSL stylesheet transforming the XML output of PubMed to Wikipedia refs.
RefTag by Apoc2400 creates a prefilled {{cite book}} template with various options from a Google Books URL. The page provides a bookmarklet for single-click transfer.
wikiciter web interface, does google books, pdf files, beta.

Citation export tools

You can insert a link beside each citation in Wikipedia, allowing you to export the citation to a reference manager such as EndNote. To install the script just add the following line to Special:MyPage/skin.js (applies to the currently selected skin) or Special:MyPage/common.js (applies to all skins)"

importScript("User:Smith609/endnote.js");

Then save the page and follow the instructions at the top of that page to bypass your browser's cache.

Notes

^ See this July 2007 discussion for more detail on why scrolling reference lists should not be used.

Wifedogging