This is material that comes from a book.[1]
References
- ^ John Doe (1990). Book of Facts. p. 21.
Wikipedia:Inline citation
 | This is an information page. It is not a Wikipedia policy or guideline; rather, its purpose is to explain certain aspects of Wikipedia's norms or practices. It may reflect varying levels of consensus. |
 | This page in a nutshell: This page describes various inline citation techniques used in Wikipedia. Some short illustrative examples can be seen at Wikipedia:Inline citation/examples. |
On Wikipedia, an inline citation is generally a citation in a page's text placed by any method that allows the reader to associate a given bit of material with specific reliable source(s) that support it. The most common method is numbered footnotes within the text, but other forms are also used on occasion.
Inline citations are often placed at the end of a sentence or paragraph. Inline citations may refer to electronic and print references such as books, magazines, encyclopedias, dictionaries and Internet pages. Regardless of what types of sources are used, they should be reliable; that is, credible published materials with a reliable editorial and publication process whose authors are generally regarded as trustworthy or authoritative in relation to the subject at hand. Verifiable source citations render the information in an article credible to readers and researchers.
The counterpart of an inline citation is what the English Wikipedia calls a general reference. This is a bibliographic citation, often placed at or near the end of an article, that provides a credible treatment of the same topic as the article. It need not be connected to any particular bit of material in an article (though it often will be); rather, it provides broad support for (or correctly informs the reading of) a substantial part or all of the article. It might also be a place for 'further reading' should a reader need a deeper treatment of the topic. It is called a "general reference" because it supports the article "in general", rather than supporting specific sentences or paragraphs ('bits of material'). General references are also to be reliable and credible, and are viewed alongside the list of footnoted sources, and in light of the fact that inline citations are used to substantiate particular materials.
When you must use inline citations
All content in articles must be verifiable. Wikipedia policy requires an inline citation to a reliable source specifically for the following four types of statements:
| Type of statement | Policy requiring inline citation |
|---|---|
| Direct quotations | Wikipedia:Verifiability |
Any statement that has been challenged (e.g., by being removed, questioned on the talk page, or tagged with {{citation needed}}, or any similar tag)
|
Wikipedia:Verifiability |
| Any statement that you believe is likely to be challenged. | Wikipedia:Verifiability |
| Contentious material, whether negative, positive, or neutral, about living persons | Wikipedia:Biographies of living persons |
Other policies, notably the copyright violations policy, prohibit the inclusion of some information, such as too-close paraphrasing, even if the material is supplied with an inline citation to a reliable source.
Our sourcing policies do not require an inline citation for any other type of material, although it is typical for editors to voluntarily exceed these minimum standards. However any material lacking an inline citation to a reliable source that directly supports the material may be removed and should not be restored without an inline citation to a reliable source. Substantially exceeding them is a necessity for any article to be granted good or featured article (or list) status. The featured article criteria, for example, require that these articles, to exemplify Wikipedia's very best work, must be "well-researched" which is defined as a "thorough and representative survey of the relevant literature" along with "consistently formatted inline citations using footnotes". If you can't find the source of a statement without an inline citation after a good-faith look, ask on the talk page, or request addition of a citation.
Technically, if an article contains none of these four types of material, then it is not required by any policy to name any sources at all, either as inline citations or as general references. For all other types of material, the policies require only that it be possible for a motivated, educated person to find published, reliable sources that support the material, e.g., by searching for sources online or at a library. However, it is rare for articles past the stub stage to contain none of these four types of material.
Editors are expected to use good judgment when determining whether material has been challenged. For example, section blanking may be considered vandalism, rather than a demand for inline citations.
- For WP:Good articles, see the five specified categories of material listed at WP:Good article criteria.
- For WP:Featured articles, see WP:When to cite.
- For WP:Featured lists, see WP:Featured list criteria.
Citation density
Wikipedia does not have a "one inline citation per sentence" or "one citation per paragraph" rule, even for featured articles. Wikipedia requires inline citations based on the content, not on the grammar and composition elements. Some articles (e.g., articles about controversial people) will require inline citations after nearly every sentence. Some sections (e.g., dense technical subjects) may even require more than one inline citation per sentence. Others may not require any inline citations at all.
For example, one inline citation is sufficient for this paragraph:
Education researcher Mary Jones says that there are three kinds of students. The first group is made up of students who do their homework as soon as they receive the assignments. The second group contains students who do their homework at the last possible second. The third group is composed of students who did not realize that they were supposed to do the assignment.[1]
Everything in that paragraph deals with the same, single subject from the same source and can therefore be supported by a single inline citation. The inline citation could be placed at any sensible location, but the end of the paragraph is the most common choice. If a subsequent editor adds information from another source to this paragraph, then it is the subsequent editor's job to organize the citations to make their relationship between the text and the sources clear, so that we maintain text-source integrity.
Text–source integrity
Using inline citations, even for statements that are not absolutely required to have inline citations, helps Wikipedia maintain text–source integrity. Using inline citations allows other people to quickly determine whether the material is verifiable, and points to where one may go to commence such verification.
The best distance between the material and the citation is a matter of judgment. If a word or phrase is particularly contentious, an inline citation may be added next to it within a sentence, but adding the citation to the end of the sentence or paragraph is usually sufficient. Remember, however, that an inline citation following a full stop tends to indicate that the quoted source is a reference for the whole sentence preceding it.
Editors should exercise caution when adding to or rearranging material to ensure that text-source relationships are maintained.
Types of inline citations
Many Wikipedia articles contain inline citations: they are required for featured articles, good articles, and A-class articles. There are many ways to add inline citations to an article. Each is acceptable under Wikipedia's citation style guideline, but a single article should use only one type. These are the most popular citation styles in Wikipedia.
Full citations in footnotes
Creating footnotes using "<ref>" tags is by far the most popular method for citing sources, and this is the type of inline citation produced by the visual editor. The full citation is in placed in a footnote (using <ref>...</ref> tags) and the footnotes appear at the bottom of the page (produced by the {{reflist}} or <references />.
Either standard wiki markup or citations templates can be used to format bibliographic citations. Either the multifeatured {{Reflist}} template or the simple <references /> code must be present on the page to indicate where the footnote should appear. Footnotes will not appear in the list unless they are placed somewhere above the {{Reflist}} or <references />. If multiple citations for the same source are included in the article, and you are using <ref> tags, you can name the footnote to link to the same note repeatedly.
Shortened footnotes
Shortened footnotes is the second most popular citation style. A short author-date citation appears in the footnote and the full reference is given in at the bottom of the page. Template {{sfn}} manages citations to different locations in the same source and combines identical footnotes automatically.
Other citation styles
Editors are free to use any citation style whatsoever (except parenthetical referencing), or to invent new citation systems if they prefer. As long as the system allows the reader to easily move from the text in a Wikipedia article to the source and verify that the source and Wikipedia agree.
Some examples include:
- Hand numbered footnotes that don't use
<ref>...</ref>, but instead use superscripts and numbers to create a similar look. - Articles with hand written HTML links and anchors to connect an inline citation with a full citation later on the page.
Inline citations in discouraged formats
Badly formatted citations verify content and should never be removed. Later editors can easily fix a badly formatted citation, but they will find it difficult or impossible to do the research necessary to find a source for a random bit of material added to an article.
These citations should be reformatted. If the source can be located using the information, then the citation should be rewritten in the citation style used by the article. (Experienced editors should not use this principle as an excuse to deliberately ignore the citation style of an article, however.)
First time editors and temporary citations
Newer editors may use any means necessary to provide a source for the material they bring to Wikipedia. Experienced editors should avoid judging or criticizing their contribution. It is only required that they provide enough information to uniquely identify the source, E.g.:
- A book: the authors name, the book's title, year of publication and the page number that the material comes from. The year is important since it establishes which edition of the book was used.
- A website: the bare URL (in brackets, i.e.
[http://example.org]) of the particular webpage on which this material appears.
These examples require almost no knowledge of Wikipedia's special characters or markup language, and no knowledge at all of proper citation formats.
This is material that comes from a book (John Doe, Book of Facts, 1990, page 21).
This is other material that comes from a website.[1]
Experienced editors should reformat these temporary citations into the citation format of the article.
Parenthetical references
This citation system was deprecated by a community discussion in 2020 and should no longer be used in new articles. However, there are many hundreds of thousands of articles which were created in this style before that time.
Inline parenthetical referencing is a citation system in which in-text citations are made using parentheses. The full bibliographic citation is then typed at the bottom of the article, usually in alphabetical order.
If you run across this format, whether in an old article or in a new contribution from an editor who hasn't yet learned other styles, please help by converting it to a non-deprecated style. This kind of conversion should not be carried out by bots. This was explicitly discouraged by the discussion.
If you don't know how to fix it yourself, then you can tag the article with {{Inline parenthetical referencing|date=July 2026}} to help more experienced editors find it.
In-text attributions without another form of inline citation
In-text attributions names the source in the sentence itself. It is a citation (in that it uniquely identifies the source) but it should be combined with another form of inline citation, typically at the end of the sentence or quotation.
Alice Jones said in her 2008 book, The Sun Is Really Big that the sun is, in fact, bigger than you think.
Alice Jones said in her 2008 book, The Sun Is Really Big that the sun is, in fact, bigger than you think.[1]
Some in-text attributions use an abbreviated form of parenthetical referencing. This is discouraged in Wikipedia.
In text attributions are used for quotations, close paraphrasing, and anything contentious or distinctive, where the editor wants to draw attention to the source's name in the article. This is most commonly used for very widely recognized classical sources, such as Shakespeare's plays, the Bible, or other primary sources with standardized numbering systems. This is also accepted in plot summaries (e.g., "The titlular character dies in Act 5").
Other discouraged types of inline citations
A few others are:
- Templates {{Ref}} and {{Note}} which were the only way to make linked footnotes before Wikipedia adopted cite.php in 2005. These still appear in about 20K+ articles.
- Bare URLs in simple brackets, e.g. [2], mentioned earlier.
See also
Wikimedia Commons has media related to Citation needed.
- Wikipedia:Manual of Style/Layout – A guideline to the basics of laying out an article.
- {{More footnotes}} — To tag a page that has some, but needs more inline citations.
- {{No footnotes}} — To tag a page that contains zero inline citations of any style.
- Wikipedia:WikiProject Inline Templates