United States. Army. Signal Corps. (1917). Machine gun shooting in air, using ring sights. [publisher not identified].
Chicago Style (17th ed.) CitationUnited States. Army. Signal Corps. Machine Gun Shooting in Air, Using Ring Sights. [Place of publication not identified]: [publisher not identified], 1917.
MLA (9th ed.) CitationUnited States. Army. Signal Corps. Machine Gun Shooting in Air, Using Ring Sights. [publisher not identified], 1917.
Warning: These citations may not always be 100% accurate.