A Uniform System of Citation: The Bluebook is the definitive style guide for legal citation in the United States. For generations, law students, lawyers, scholars, judges, and other legal professionals have relied on The Bluebook's uniform system of citation in their writing. In a diverse and rapidly changing legal profession, The Bluebook continues to provide a systematic method by which members of the profession communicate important information to one another about the sources and legal authorities upon which they rely in their work.
ALWD Guide to Legal Citation by 
The Bluebook by 