An online guide from CUNY's Lehman College with resources on citing government documents.

The Chicago Manual of Style calls The Bluebook (published by the Harvard Law Association) the most widely used citation guide whose conventions predominate in law reviews. In addition to the CMOS Online guide, see the Purdue OWL's summary of the CMOS's guidance for using The Bluebook style.

A comprehensive guide from the GC Library on citing digital sources.

Geared towards NARA holdings, but useful for citing manuscript and archival materials from other repositories.

Hacker, Diana, and Barbara Fister. Research and Documentation in the Digital Age. Sixth edition. Boston; Bedford/St. Martin’s, 2015.