This page is a style guide, describing how to write citations in articles. Providing sources for edits is mandated byWikipedia:No original research andWikipedia:Verifiability, which are policy. What this means is that any material that is challenged and has no source may be removed by any editor. See those pages andWikipedia:Identifying reliable sources for more information.

Citing sources serves several purposes:

• To ensure that the content of articles is credible and can be checked by any reader or editor.
• To enhance the overall credibility and authoritative character of Wikipedia.
• To show that your edit isn'toriginal research.
• To reduce the likelihood of editorial disputes, or toresolve any that arise.
• To credit a source for providing useful information and to avoid claims ofplagiarism.
• To provide more information or further reading.

Wikiquote articles should not use articles from other Wikimedia projects as sources. Wikilinks are not a substitute for sources.

If you add any information to an article, particularly if it's contentious or likely to be challenged, you should supply a source. If you don't know how to format the citation, others will fix it for you. Simply provide any information you can on the source.

In general, even if you are writing from memory, you shouldactively search for authoritative references to cite. If you are writing from your own knowledge, then you should know enough to identify good references that the reader can consult on the subject — you will not be around forever to answer questions. The main point is tohelp the reader and other editors.

The need for citations is especially important when writing about the opinions held on a particular issue.Avoid weasel words such as, "Some people say…" Instead, make your writingverifiable: find a specific person or group who holds that opinion, mention them by name, and give a citation to some place where they can be seen or heard expressing that opinion. Remember that Wikiquote is not a place for expressing your opinions or fororiginal research.

Because this is the English Wikiquote, English-language sources should be given whenever possible, and should always be used in preference to foreign-language sources of equal calibre. However, do give foreign-language references where appropriate. If quoting from a foreign-language source, an English translation should be given with the original-language quote beside it.

You canadd sources even for material you didn't write if you use a source toverify that material. Adding sources to an article is an excellent way to contribute to Wikiquote.

Disputed edits can be removed immediately, removed and placed on the talk page for discussion, or where the edit is harmless but you dispute it and feel a citation is appropriate, you can place {{fact}} after the relevant passage. This should be used sparingly; Wikiquote has a lot of undercited articles, and inserting many of instances of {{fact}} is unlikely to be beneficial.

Think ahead: Try to imagine whether people might doubt what you wrote or need more information. Supporting what is written in Wikiquote by referring to a clear and reliable source will add stability to your contribution.

For an easy-follow guide, seeWikipedia:Citing sources/example style

If you are the first to add references to an article, try to follow conventions generally accepted in the field of knowledge described in the article. Some of these might follow from formats proposed byWikiProjects.

If nothing in particular appears applicable, or if you don't know which style would work best:

• The examples given inWikipedia:Citing sources/example style might be helpful.
• Consider using thetemplates provided byw:Wikipedia:Template messages/Sources of articles#Citations of generic sources.

The system of presenting references in a Wikipedia article may change over time; it is more important to have clarity and consistency in an article than to adhere to any particular system.

Sometimes — for example, when the article treats an uncontroversial or simple topic, and draws on a few, widely accepted general sources — it is sufficient to provide a "References" section at the end of the article, containing an alphabetized list of general references and authoritative overviews of a subject (such as textbooks and review articles). In other cases this is not enough, andin addition you should use in-line citations such as theHarvard references orfootnotes described below.

Remember though:the most important thing is to enter comprehensive reference information — that is, enough information so that a reader can find the original source with relative ease.

There are several ways of accomplishing this.

• When writing a new article or adding references to an existing article that has none, follow theestablished practice for the appropriate profession or discipline that the article is concerning (if available and unquestioned).
• An article's previous content contributors usually know the established practice - if possible, follow their lead if the article already has references.
• If the established practice is unavailable or disputed, contributors should decide on a style that they believe strikes an appropriate balance between preserving the readability of the text and making citations as precise and accessible as possible.
• If contributors differ as to the appropriate style of citation, they should defer to the article's maincontent contributors in deciding the most suitable format for the presentation of references.
• If no agreement can be reached, the style used should be that of the first major contributor.

If you are unclear as to which system or style to use, remember: the most important thing is to provide all the information one would need to identify and find the source. If necessary, put this information in the talk page, or in a comment on the main page, and ask others how to format it correctly for that article.

The following are different methods that you can use to insert references in Wikipedia articles.

The three most popular styles of in-text citations areHarvard style,footnotes, andembedded HTML links.

Note that no matter which inline-citation style is used, all the sources used in an article should be listed at the end in a references section.

The MediaWiki software supports embedding HTML links directly into an article by enclosing a URL with single square brackets — [http://www.google.com] — which appears like this:[1] A full citation ought then be given in the References section like this:

*[http://google.com Google's website], which appears as:

• Google's website

A newspaper article referenced in an article by using an embedded link might be — [http://media.guardian.co.uk/site/story/0,14173,1601858,00.html] — which looks like this.[2] The embedded link is placed after the period, or when placed within a sentence after a clause, then after the comma.

Then in the References section, a full citation is provided:

*[http://media.guardian.co.uk/site/story/0,14173,1601858,00.html "Sorrell accuses Murdoch of panic buying"] by John Plunkett, ''The Guardian'', October 27, 2005, retrieved October 27, 2005

which appears as:

• "Sorrell accuses Murdoch of panic buying" by John Plunkett,The Guardian, October 27, 2005, retrieved October 27, 2005

It is particularly important in the case of online newspaper articles to include byline, headline, newspaper, and date of publication, because many newspapers keep stories online only for a certain period before transferring them to the archives. With a full citation, readers will be able to find the article easily even if the link doesn't work.

It's also important to provide and place in quotation marks the headline of the article, or title if it's a scholarly paper, so that Wikipedia is attributing a description of the article's contents to a source, and not describing it ourselves. For example, it isn't Wikipedia's claim that Sorrell is accusing Murdoch of panic buying, but theGuardian's, and we should precisely quote theGuardian's headline, and not replace it with "A story about Murdoch's panic buying".

An advantage of these embedded links is that it is easy for an online reader and other editors to click on the link and jump immediately to the cited article (if still working). In principle, this makes checking sources very easy. Another advantage of these embedded links is that they are easy to create and maintain.

There are disadvantages with such embedded links, however. First, there is question of how much such checking and maintenance takes place: anyone who takes a random sample of these will find dead embedded links. Also, such links do not normally provide all the information that a traditional citation would have; thus, if the material moves or is dramatically changed, it can be difficult to rediscover the cited material, which is why it is particularly important to include a full citation in the References section.

The Harvard referencing system places a partial citation — the author's name and year of publication within parentheses — in the text itself, and a complete citation at the end of the text in an alphabetized list of "References". According toThe Oxford Style Manual, the Harvard system is the "most commonly used reference method in the physical and social sciences" (Ritter 2002).

• For one author, add the author's surname and the year of publication in parentheses (roundbrackets) after the sentence or paragraph, and before the period: for example (Smith 2005).
• For two authors, use (Smith & Jones 2005); for more authors, use (Smith et al. 2005).
• If the "References" section contains two or more works by the same author but published the same year, use a letter after the year to distinguish the different sources (for example, (Smith 2005a) and (Smith 2005b).Make sure that the in-text citations use the correct letters that correspond to the full citation in the "References" at the end of the article.

• If the date of publication is unavailable, use "n.d." (meaning, no date)
• Many times authors use an edition of a book that was published long after the original publication. In such cases, many people put the original date of publication in square brackets followed by the date of publication of the edition used by the author who is making the citation. For example, a citation might be

(Marx [1867] 1967)

and the complete reference would be:

Marx, Karl [1867] 1967 Capital: A Critique of Political Economy Vol. I. Edited by Frederick Engels. New York: International Publishers.

• When providing a page number, the convention is (Smith 2005:73).
• For a quotation that is within the text and marked by quotation marks, the citation follows the end-quotation mark ("), and preceeds the period (.)
• For a quotation that is indented, the citation follows the period.
• When the author of the reference is named as part of the text itself, put the year in parentheses; for example "Smith (2005) says ..."

Note: Harvard referencing is not complete without the full citation at the end of the page (article) in the References section.

Complete citations, also called "references," are collected at the end of the article under a ==References== heading. Under this heading, list the comprehensive reference information as a bulleted (*) list, one bullet per reference work.

References typically include: the name of the author, the title of the book or article, the name of the publisher, and the date of publication. Different professions, academic disciplines, and publishers have different conventions as to the order in which this information should be arranged, or whether additional information is required. Usually, the list is in alphabetical order by the author's surname.

Typical references could be:

• L. Husseinet al (1999) . ""Nutritional quality and the presence of anti-nutritional factors in leaf protein concentrates (LPC)"".International Journal of Food Sciences and Nutrition50 (5): 333–343.
• McDougall, D. (2003)."Trauma of quake's shattered children".Guardian. Retrieved October 23, 2005.
• Smith, J.How to cite your sources, Random House, 2005.ISBN 1607000X Invalid ISBN

For more templates to assist formatting, seethe citation templates.

Citations for newspaper articles typically include the title of the article in quotes, thebyline (author's name), the name of the newspaper in italics, date of publication, and the date you retrieved it if it's online.

Some books have been reprinted several times over the course of the years. Sometimes they have gone through several editions, and sometimes a book may be published by several different publishers. This can raise serious problems for citations, because different editions may be paginated differently. Ideally, all citations in a given article should refer to the same edition by the same publisher, and this edition information should be included in the reference at the end of the article and/or theISBN (see there) should be given. That way, there would be no confusion over the correct page number for cited quotes or material.

• If the "References" section contains two or more works by the same author but published the same year, use a letter after the year to distinguish the different sources (for example 2005a and 2005b).
• If you do not know the date of publication, try to find it (you could try your local library, the web-page of a national library such as the Library of Congress, or Amazon.com)
• If the date of publication is unavailable, use "n.d." (meaning, no date)
• Many times authors use an edition of a book that was published long after the original publication. In such cases, theymust provide the date of the edition they are using or else the ISBN, and preferably both. This is important because different editions may be paginated differently.
• When contributors use an edition of a book that was published long after the original publication, theymay put the original date of publication in square brackets followed by the date of publication of the edition used by the author who is making the citation. For example, an in-line citation might be

(Marx [1867] 1967)

and the complete reference would be:

Marx, Karl [1867] 1967 Capital: A Critique of Political Economy Vol. I. Edited by Frederick Engels. New York: International Publishers.

As Wikipedia grows it is likely that different editors may rely on different editions of the same book.

• Usually, different editions of the same book are published in different years. In such cases knowing the year is enough information to distinguish the different editions.
• Sometimes, different editions of the same book are published in the same year. This often happens after a copyright has expired, and different publishing companies publish different editions. In such cases, one must know the publisher to distinguish the different editions, or else the ISBN.

It is crucial that complete references be provided for each distinct edition referred to (or cited) in the article, and that each such in-line citation provide enough information to distinguish between editions.

Template:Details

Many publications in a wide range of fields use numbers — in square brackets and/or superscripted — to refer to a list of citations at the end of the article, e.g.Template:Ref label or[1] with:

1. ^ Template:Journal reference issue

Citations using numbered footnotes are controversial in Wikipedia for several reasons:

1. Until recently, the MediaWiki software had limited footnote support. In particular,automatic numbering of footnotes conflicted with use of embedded HTML links in single square brackets with automatic numbering, and the same footnote cannot be used multiple times with automatic numbering. In contrast, the software could already support the Harvard style without issue.
   • This appears now to have been addressed bythe new <ref> element.
2. Many of today's style guides forbid or deprecate footnotes and reference endnotes when used simply to cite sourcesTemplate:Ref harvard. TheAPA style does not use footnotes to cite sources.The MLA style manual has deprecated reference footnotes and reference endnotes for decades in favor of in-line bibliographic references.
3. Footnotes are normally simply numbered numerically. Thus, determining who said what typically requires a reader to continually jump back and forth between the main body and the footnote/endnote to see if there is something of value. When footnotes are simply providing a much more detailed argument, this is often not a problem, but if the footnotes are the primary citation method, this can be critical (since it is sometimes important to keep track of who claims what).

Note: If a Wikipedia article does use footnotes, the footnotes in their own section must include the normal source citations just as in the "References" section for otherinline citations above.

• Some publications use footnotes for both the full citation of a source, and for tangential comments or information of interest to the reader.
• Some publications useHarvard style notation for sources, and use footnotes exclusively for tangential comments or information of interest. In this case, in other words, footnotes are notes with relevant text that would distract from the main point if embedded in the main text, yet are helpful in explaining a point in greater detail. Such footnotes can be especially helpful for later fact-checkers, to ensure that the article text is well-supported. Thus, using footnotes to provide useful clarifying information outside the main point is fine where this is needed.

Technically, footnotes appear at the bottom of a page; endnotes appear at the end of a chapter or book. Since wikipedia articles may be considered to consist of one long page, or of no pages at all, Wikipedia footnotes appear at the end of an article, but are nevertheless called footnotes.

Recommended section names to use for footnotes in Wikipedia:

• ==Notes== section: Used for footnotes which are not full citations of sources.
• ==Notes and references== section: Used if there is no separate section with general references,and if all sources of the general content of the article are covered by the footnotes.
• ==Footnotes== section: Used for all other cases.

The ==External links== section is placed after the references section, and offers links to websites related to the topic that might be of interest to the reader, but whichhave not been used as sources for the article.

Numbered links

AURL surrounded by single square brackets displays as a clickable number between square brackets followed by an arrow, and leads to the webpage mentioned in the URL. For example, [http://en.wikipedia.org/wiki/Wikipedia:Cite_sources] renders as[3]. Note that inline links of this kind are placed after the punctuation, not before it, like this.[4]

Or, links displaying a text

Seew:Wikipedia:Cite sources/example style#Web sites and articles (not from periodicals). Of course, a Harvard style reference can be the displayed clickable text for an external link, if the referenced work is available on-line.

When a link in the External links/Further reading sections "goes dead", it is not a serious matter, and it can be removed from the article. Reference-section links (i.e. links to sources actually used to support material) in the article are another matter. In general, they are still worth keeping as part of the referencing apparatus of the article; often, a live substitute link can be found. Here are some pointers. In most cases, these approaches will preserve an acceptable citation.

• A very large proportion of pages can be recovered from theInternet Archive. Just go tohttp://www.archive.org/ and search for the old link by URL. Make sure that your new citation mentions the date the page was archived by the Internet Archive.
• If this was a non-blind citation of web-only material, it may be worth the effort to search the target site for an equivalent page at a new location, an indication that the whole site has moved, etc.
• If the link was merely a "convenience link" to an online copy of material that originally appeared in print, and an appropriate substitute cannot be found, it is acceptable to drop the link but keep the citation.
• If you cannot find the page on the Internet Archive, remember that you can often find recently deleted pages inGoogle's cache. They won't be there long, and it is no use linking to them, but this may let you find the content, which can be useful in finding an equivalent page elsewhere on the Internet and linking to that.

If none of those strategies succeed, do not remove the inactive reference, but rather record the date that the original link was found to be inactive — even inactive, it still records the sources that were used, and it is possible hard copies of such references may exist, or alternatively that the page will turn up in the near future in the Internet Archive, which deliberately lags by six months or more. Note also that whilst many printed sources become outdated, scholars still routinely cite those works when referenced.

If an article needs references but you are unable to find them yourself, you can tag the article with the templates {{unreferenced}} or {{Primarysources}}. It is often more useful to indicate specific statements that need references, by tagging those statements with {{fact}}, which can be placed in the same place you would place an inline reference.

For suggestions on how to cite Wikipediain other works, seew:Wikipedia:Citing Wikipedia; the toolw:Wikipedia:Special:Cite is also available there to help you.

• Wikiquote:Sourcing

• Concordia Libraries (Concordia University).Citation and Style Guides. Retrieved December 28, 2004. (This provides a list of common citation styles.)
• Citation Styles Handbook: APA
• Citation Styles Handbook: MLA
• APA Style.org
• Using American Psychological Association (APA) Format (Updated to 5th Edition)
• Citing Electronic Documentation (APA, Chicago, MLA)
• The Columbia Guide to Online Style
• Ritter, R. (2002) The Oxford Style Manual, Oxford University Press.ISBN 0198605641

• Psychology with Style: A Hypertext Writing Guide
• A Guide for Writing Research Papers Based on Modern Language Association (MLA) Documentation
• AMA Citation Style
• Chicago/Turabian Documentation
• Citation Guide - Turabian (.PDF file)
• General Guidelines for Citing Government Publications
• Guide to Citation Style Guides
• Sociology style (ASR)
• Uniform Requirements for Manuscripts Submitted to Biomedical Journals
• American Chemical Society reference style guidelines

• Policy drafts