United States. Bureau of Mines. (1936). Progress report no. 2 on investigation of detachable rockdrill bits. [s.n.].
Chicago Style (17th ed.) CitationUnited States. Bureau of Mines. Progress Report No. 2 on Investigation of Detachable Rockdrill Bits. [Washington]: [s.n.], 1936.
MLA (9th ed.) CitationUnited States. Bureau of Mines. Progress Report No. 2 on Investigation of Detachable Rockdrill Bits. [s.n.], 1936.
Warning: These citations may not always be 100% accurate.