For computer people working with legal documents, the first and most difficult thing to understand is that American legal citations are not unique document identifiers, and cannot be used that way. They are instead a kind of document address, or a place to look where you might find a document. They are based on the volume and page number where a case may be found in a series of printed books. Because more than one case may appear on a page -- sometimes many more, when the page is a tabular reference to numerous minor cases -- there is no guarantee of uniqueness.
More sensible schemes that are both vendor and media-neutral have been suggested and are implemented in different jurisdictions (yes, this is a jurisdiction-by-jurisdiction problem). Most are based in some way on the American Association of Law Libraries (AALL) Universal Citation Guide, 2nd ed.
Learning aids and guides
For print-based citation, try:
- Peter Martin's Basic Legal Citation
- The HLSL guide to legal citations
- The Bluebook (18th ed.), which is considered the definitive print reference.
Abbreviations figure heavily in legal citation. A number of good lists are available: