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 September 23, 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.