United States. Bureau of Mines. (1939). Mine Safety Board decision 30: Main fan installations at coal mines. [s.n.].
Chicago Style (17th ed.) CitationUnited States. Bureau of Mines. Mine Safety Board Decision 30: Main Fan Installations at Coal Mines. [Washington]: [s.n.], 1939.
MLA (9th ed.) CitationUnited States. Bureau of Mines. Mine Safety Board Decision 30: Main Fan Installations at Coal Mines. [s.n.], 1939.
Warning: These citations may not always be 100% accurate.