APA (7th ed.) Citation

United States. Bureau of Mines. (1931). National safety competition of 1930. [publisher not identified].

Chicago Style (17th ed.) Citation

United States. Bureau of Mines. National Safety Competition of 1930. [Washington]: [publisher not identified], 1931.

MLA (9th ed.) Citation

United States. Bureau of Mines. National Safety Competition of 1930. [publisher not identified], 1931.

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