Wikipedia:BLUE

Not citing common knowledge and not providing bibliographic entries for very famous works is also consistent with the major academic style guides, such as The MLA Style Manual and the APA style guide.

Sometimes editors will insist on citations for material simply because they dislike it or prefer some other material, not because the material in any way needs verification. For example, an editor may demand a citation for the fact that most people have five digits on each hand (yes, this really happened). Another may decide that the color of the sky is actually aqua rather than blue, pull out an assortment of verifiable spectrographic analyses and color charts to demonstrate that this position is actually correct, and follow that with a demand that other editors provide equivalent reliable sources for the original statement that the sky is in fact blue. While there are cases where this kind of pedantic insistence is useful and necessary, often it is simply disruptive, and can be countered simply by pointing out that there is no need to verify statements that are patently obvious. If the alternate proposition merits inclusion in the article under other policies and guidelines it should of course be included, but it should in no way be given greater prominence because it is sourced.

Verification tags should not be used in a POINTed fashion. Use only those tags necessary to illustrate the problem, and discuss the matter in detail on the talk page.

Citations should be evaluated on the qualities they bring to the article, not on the quantity of citations available. The first 1 or 2 citations supporting a given point are informative; extra citations after that begin to be argumentative. Keep in mind that the purpose of a citation is to guide the reader to external sources where the reader can verify the idea presented, not to prove to other editors the strength of the idea. Extra sources for the same idea should be added to 'Further Reading', 'See Also', or 'External Sources' sections at the bottom of the page, without explicitly being cited in the text.

A common misconception when improving an article, particularly towards Good Article status, is that everything must be cited to an inline source, which leads to comments such as "the end of paragraph 3 is uncited", without specifying why that is an issue. In fact, the Good Article criteria merely state that inline citations are required for "direct quotations, statistics, published opinion, counter-intuitive or controversial statements that are challenged or likely to be challenged, and contentious material relating to living persons". While that covers much, most, or possibly even (in the case of biographies of living people) all content in an article, it does not imply that you must cite everything everywhere for every single article, period.

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