Help:Introduction to referencing with Wiki Markup/1
One of the key policies is that all article content has to be verifiable. This means that reliable sources must be able to support the material. All quotations, any material whose verifiability has been challenged or is likely to be challenged, and contentious material (whether negative, positive, or neutral) about living persons must include an inline citation to a source that directly supports the material. This also means that Wikipedia is not the place for original work, archival findings that have not been published, or evidence from any source that has not been published.