APA (7th ed.) Citation

United States. Army. Signal Corps. (2013). Visual Signaling. Project Gutenberg.

Chicago Style (17th ed.) Citation

United States. Army. Signal Corps. Visual Signaling. Project Gutenberg, 2013.

MLA (9th ed.) Citation

United States. Army. Signal Corps. Visual Signaling. Project Gutenberg, 2013.

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