The Bluebook: A Uniform System of Citation is the preferred method of citation for legal documents and scholarship in the United States. Georgetown Law Library provides a great overview of The Bluebook and the basic concepts of legal citation for cases, statutes, and other resources.
Indigo = blue. Get it?!? A free, Creative Commons-dedicated implementation of The Bluebook’s Uniform System of Citation. The Indigo Book was compiled by a team of students at the NYU School of Law, working under the direction of Professor Christopher Jon Sprigman.
Formal legal citations must be made in Bluebook format, however if you need to cite your sources using another format, the library has pulled together a bunch of resources to assist you on a variety of citation formats.