The National Industrial Security Program Operating Manual, or NISPOM, is the guide for all Cleared Defense Contractors, or CDCs.
Two executive orders that pertain to CDCs are E.O. 12829, which defines the Industrial Security Program and was amended by E.O. 12885, and E.O. 13526, which provides guidance for classified information.
The SF 312 Briefing Book discusses how to protect classified information.
Homeland Security Presidential Directive 12 outlines the standards for identification and access to U.S. government facilities.