APA (7th ed.) Citation

United States. Bureau of Mines. (1941). Some essential safety factors in tunneling. [s.n.].

Chicago Style (17th ed.) Citation

United States. Bureau of Mines. Some Essential Safety Factors in Tunneling. [Washington]: [s.n.], 1941.

MLA (9th ed.) Citation

United States. Bureau of Mines. Some Essential Safety Factors in Tunneling. [s.n.], 1941.

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