APA (7th ed.) Citation

United States. Bureau of Mines. (1939). Multiple-­shift mechanical mining in some bituminous coal mines, progress report 2. [s.n.].

Chicago Style (17th ed.) Citation

United States. Bureau of Mines. Multiple-­shift Mechanical Mining in Some Bituminous Coal Mines, Progress Report 2. [Washington]: [s.n.], 1939.

MLA (9th ed.) Citation

United States. Bureau of Mines. Multiple-­shift Mechanical Mining in Some Bituminous Coal Mines, Progress Report 2. [s.n.], 1939.

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