Books by Robert H. Ridgway:
Books in the extended shelves:
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Ridgway, Robert H. (Robert Henderson): Manganese : general Information (U.S. Dept. of the Interior, Bureau of Mines, 1933) (page images at HathiTrust)- Ridgway, Robert H. (Robert Henderson): Mineral economics series. [No.] 3, Consumption of ferrous scrap and pig iron in the United States in 1937 (U.S. Dept. of the Interior, Bureau of Mines, 1938), also by M. E. Trought, H. W. Davis, and United States Bureau of Mines (page images at HathiTrust)
- Ridgway, Robert H. (Robert Henderson): Pyrites : general information (U.S. Dept. of the Interior, Bureau of Mines, 1931), also by United States Bureau of Mines (page images at HathiTrust)
- Ridgway, Robert H. (Robert Henderson): Shifts in sources of chromite supply (U.S. Dept. of the Interior, Bureau of Mines, 1936) (page images at HathiTrust)
- Ridgway, Robert H. (Robert Henderson): Sulphur : general information (U.S. Dept. of Commerce, Bureau of Mines, 1930) (page images at HathiTrust)
Find more by Robert H. Ridgway at your library, or elsewhere.