APA (7th ed.) Citation

United States. Army. Air Corps. (1921). Observations from captive balloons. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Army. Air Corps. Observations from Captive Balloons. Washington: U.S. GPO, 1921.

MLA (9th ed.) Citation

United States. Army. Air Corps. Observations from Captive Balloons. U.S. GPO, 1921.

Warning: These citations may not always be 100% accurate.