A citation is a line of text that uniquely identifies a source. For example: Ritter, Ron. The Oxford Style Manual. Oxford University Press, 2002, p. 1. When to cite sources: The policy on sourcing is Verifiability, which requires inline citations for any material challenged or likely to be challenged, and for all quotations. The policy is strictly applied to all material in the mainspace—articles, lists, captions, and sections of articles—without exception. In the event of a contradiction between this page and the policy, the policy takes priority, and this page should be updated to reflect it. Sourcing also applies to images: when an image is uploaded, the uploader must say where the image came from and indicate its copyright status.