The list of featured-article criteria calls for inline citations where appropriate. The English Wikipedia's Verifiability policy requires inline citations for quotations, whether using direct or indirect speech, and for material that is challenged or likely to be challenged. Editors are also advised to add in-text attribution whenever a source's words are copied or closely paraphrased. You can make clear which sources support your article using:

  • INCITE: Cite your sources in the form of an inline citation after the phrase, sentence, or paragraph in question.
  • INTEXT: Add in-text attribution whenever you copy or closely paraphrase a source's words.
  • INTEGRITY: Maintain text–source integrity by placing inline citations in a way that makes clear which source supports which part of the text.

When a source is needed

See also: Wikipedia:You do need to cite that the sky is blue

Material that is actually challenged by another editor requires a source or it may be removed; and anything likely to incur a reasonable challenge should be sourced to avoid disputes and to aid readers (see WP:BURDEN). In practice, this means most such statements are backed by an inline citation. In case of multiple possible references for a statement, the best reliable sources should be used.

  • Surprising or apparently important claims not covered by mainstream sources;
  • Reports of a statement by someone that seems out of character, embarrassing, controversial, or against an interest they had previously defended;
  • Claims that are contradicted by the prevailing view within the relevant community, or which would significantly alter mainstream assumptions, especially in science, medicine, history, politics, and biographies of living persons, and especially when proponents consider that there is a conspiracy to silence them.

When a source or citation may not be needed

See also: Wikipedia:You don't need to cite that the sky is blue, Wikipedia:Likely to be challenged, and Wikipedia:The Pope is Catholic

Citations in leads

Main page: Wikipedia:Manual of Style/Lead section

Because the lead will usually repeat information also in the body, editors should balance the desire to avoid redundant citations in the lead with the desire to aid readers in locating sources. Leads are usually written at a greater level of generality than the body, and information in the lead section of non-controversial subjects is less likely to be challenged and less likely to require a source. There is not, however, an exception to citation requirements specific to leads. Complex, current, or controversial subjects may require many citations; others, few or none. Contentious material about living persons must always be cited, regardless of the level of generality.

Text–source relationship

Main page: Wikipedia:Citing sources § Text–source integrity

The distance between material and its source is a matter of editorial judgment. The source of the material should always be clear, and editors should exercise caution when rearranging cited material to ensure that the text–source relationship isn't broken.

If you write a multi-sentence paragraph that draws on material from one source, the source need not be cited after every single sentence unless the material is particularly contentious. When multiple sources are used within a paragraph, these can be bundled into a single footnote if desired, so long as the footnote makes clear which source supports which points in the text.

Challenging another user's edits

See also