APA (7th ed.) Citation

United States. Bureau of Mines. (1940). International coal trade, Jan. 31, 1940. [s.n.].

Chicago Style (17th ed.) Citation

United States. Bureau of Mines. International Coal Trade, Jan. 31, 1940. [Washington]: [s.n.], 1940.

MLA (9th ed.) Citation

United States. Bureau of Mines. International Coal Trade, Jan. 31, 1940. [s.n.], 1940.

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