United States. Defense Protective Service. (2002). 9-11 special edition. Defense Protective Service.
Chicago Style (17th ed.) CitationUnited States. Defense Protective Service. 9-11 Special Edition. [Washington, D.C.]: Defense Protective Service, 2002.
MLA (9th ed.) CitationUnited States. Defense Protective Service. 9-11 Special Edition. Defense Protective Service, 2002.
Warning: These citations may not always be 100% accurate.