Cited Reference searching is the ability to search the list of references (or footnotes) found in journal articles, books, dissertations, websites, etc. It is based on the premise that you have a scholarly work in-hand that you really like and you want to see who else has used that work in their research - ergo, have included it in their list of references (or footnotes). Typically, cited reference searching involves looking for works by a particular author or for a specific piece.
The 3 "main" databases below each have their strengths and weaknesses. None of them should be used exclusively.