Airplanes - Hangars - A gigantic dirigible hangar. This hangar is designed to accommodate three dirigibles. The power plant at the left of the picture furnished power and light for the aviation camp and generates gas for the big bags of the dirigibles. Observe the lookout posted on the hangar

Chicago citation style
War Department. 1789-9/18/1947. Airplanes - Hangars - A gigantic dirigible hangar. This hangar is designed to accommodate three dirigibles. The power plant at the left of the picture furnished power and light for the aviation camp and generates gas for the big bags of the dirigibles. Observe the lookout posted on the hangar. 1917-01-01/1918-12-31. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/17338928. (Accessed December 14, 2018.)
APA citation style
War Department. 1789-9/18/1947, (1917-01-01/1918-12-31) Airplanes - Hangars - A gigantic dirigible hangar. This hangar is designed to accommodate three dirigibles. The power plant at the left of the picture furnished power and light for the aviation camp and generates gas for the big bags of the dirigibles. Observe the lookout posted on the hangar. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/17338928
MLA citation style
War Department. 1789-9/18/1947. Retrieved from the Digital Public Library of America <http://catalog.archives.gov/id/17338928>.
Note: These citations are programmatically generated and may be incomplete.