Department of Defense
Communications Intelligence Activities (Memo creating the National Security Agency, October 24, 1952)
NSA/CSS Policy 1-23, Procedures Governing NSA/CSS Activites that Affect U.S. Persons, National Security Agency/Central Security Service (revised, March 11, 2004)
Marine Corps Warfighting Publication (MCWP) 2-22, Signals Intelligence (1999)
NAVMC Directive 3500. 41, Signals Intelligence Training and Readiness Manual, (August 20, 2004)
Electronic Intelligence (ELINT) at NSA (National Security Agency)
National Security Agency (NSA) SIGINT Reporter's Style and Usage Manual, 2010
Maritime SIGINT Architecture Technical Standards Handbook, Version 1.0 (National Security Agency, Marcy 1999)
Articles
All Glory is Fleeting: Sigint and the Fight Against International Terrorism, Matthew Aid, Intelligence and National Security, Vol. 18, No. 4 (Winter 2003), p. 72-120.
Signals Intelligence Support to the Cockpit (CPT Gilles Van Nederveen, College of Aerospace Doctrine, Research, and Education, Airpower Research Institute, Maxwell Air Force Base, Alabama)
Other Resources
The Chinese People's Liberation Army Signal Intelligence and Cyber Reconnaissance Infrastructure, Mark A. Stokes, Jenny Lin, L.C. Russell Hsaio (Project 2049 Institute, November 11, 2011)
Working Paper No. 5, The Origins of Signals Intelligence in New Zealand, Nicky Hager (August 1995)
Canadian SIGINT Contributions to the UKUSA Partnership, Coridon Henshaw
News, commentary, and links to sources relevant to the legal aspects of foreign intelligence-gathering.
