United States. Bureau of Mines. (1939). Some of welfare problems of mining industry and what Bureau of Mines has done about them. [s.n.].
Chicago Style (17th ed.) CitationUnited States. Bureau of Mines. Some of Welfare Problems of Mining Industry and What Bureau of Mines Has Done About Them. [Washington]: [s.n.], 1939.
MLA (9th ed.) CitationUnited States. Bureau of Mines. Some of Welfare Problems of Mining Industry and What Bureau of Mines Has Done About Them. [s.n.], 1939.
Warning: These citations may not always be 100% accurate.