Security force troops from 21st Space Wing, Peterson Air Force Base, Colorado, prepare to aim for a satellite dish target during the marksmanship competition of GUARDIAN CHALLENGE 2001, at Vandenberg Air Force Base, California. GUARDIAN CHALLENGE, the world's premier space and missile competition, is a four-day event hosted annually at Vandenberg AFB, CA "to recognize the best and demonstrate the commands warfighting skills. GUARDIAN CHALLENGE creates competition-tough crews; improves readiness and combat capabilities through preparation, innovation and sharing; enhances esprit de corps and strengthens teamwork across all mission areas in the command."

Chicago citation style
Department of Defense. American Forces Information Service. Defense Visual Information Center. 1994-. Security force troops from 21st Space Wing, Peterson Air Force Base, Colorado, prepare to aim for a satellite dish target during the marksmanship competition of GUARDIAN CHALLENGE 2001, at Vandenberg Air Force Base, California. GUARDIAN CHALLENGE, the world's premier space and missile competition, is a four-day event hosted annually at Vandenberg AFB, CA "to recognize the best and demonstrate the commands warfighting skills. GUARDIAN CHALLENGE creates competition-tough crews; improves readiness and combat capabilities through preparation, innovation and sharing; enhances esprit de corps and strengthens teamwork across all mission areas in the command.". 2001-05-08. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/6600381. (Accessed May 27, 2018.)
APA citation style
Department of Defense. American Forces Information Service. Defense Visual Information Center. 1994-, (2001-05-08) Security force troops from 21st Space Wing, Peterson Air Force Base, Colorado, prepare to aim for a satellite dish target during the marksmanship competition of GUARDIAN CHALLENGE 2001, at Vandenberg Air Force Base, California. GUARDIAN CHALLENGE, the world's premier space and missile competition, is a four-day event hosted annually at Vandenberg AFB, CA "to recognize the best and demonstrate the commands warfighting skills. GUARDIAN CHALLENGE creates competition-tough crews; improves readiness and combat capabilities through preparation, innovation and sharing; enhances esprit de corps and strengthens teamwork across all mission areas in the command.". Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/6600381
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/6600381>.
Note: These citations are programmatically generated and may be incomplete.