Two US Air Force (USAF) Security Police (SP) assigned to the 310th Space Group (SG) "Bombardiers" armed with 5.56mm M16A2 rifles don their MCU-2P gas mask during a simulated gas attack on the security forces marksmanship competition course, at Vandenberg Air Force Base (AFB) California (CA), during Exercise GURRDIAN CHALLENGE 2002. Guardian Challenge, a four-day space and missile competition, is hosted annually at Vandenberg AFB, CA to test the wartime readiness of Air Force Space Command (AFSPC) professionals

Chicago citation style
Department of Defense. American Forces Information Service. Defense Visual Information Center. 1994-. Two US Air Force (USAF) Security Police (SP) assigned to the 310th Space Group (SG) "Bombardiers" armed with 5.56mm M16A2 rifles don their MCU-2P gas mask during a simulated gas attack on the security forces marksmanship competition course, at Vandenberg Air Force Base (AFB) California (CA), during Exercise GURRDIAN CHALLENGE 2002. Guardian Challenge, a four-day space and missile competition, is hosted annually at Vandenberg AFB, CA to test the wartime readiness of Air Force Space Command (AFSPC) professionals. 2002-05-06. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/6629020. (Accessed July 19, 2018.)
APA citation style
Department of Defense. American Forces Information Service. Defense Visual Information Center. 1994-, (2002-05-06) Two US Air Force (USAF) Security Police (SP) assigned to the 310th Space Group (SG) "Bombardiers" armed with 5.56mm M16A2 rifles don their MCU-2P gas mask during a simulated gas attack on the security forces marksmanship competition course, at Vandenberg Air Force Base (AFB) California (CA), during Exercise GURRDIAN CHALLENGE 2002. Guardian Challenge, a four-day space and missile competition, is hosted annually at Vandenberg AFB, CA to test the wartime readiness of Air Force Space Command (AFSPC) professionals. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/6629020
MLA citation style
Department of Defense. American Forces Information Service. Defense Visual Information Center. 1994-. Retrieved from the Digital Public Library of America <http://catalog.archives.gov/id/6629020>.
Note: These citations are programmatically generated and may be incomplete.