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por Shedd, Solon, 1860-1941
Publicado 1924 -
Coal in Washington;distribution geology mining preparation uses and economic value of coal resources of WashingtonBookpor Daniels, Joseph, 1884-1965
Publicado 1934 -
Report on the mining industries of the United States (exclusive of the precious metals)with special investigation into the iron resources of the republic and into the Cretaceous coals of the NorthwestBookpor Pumpelly, Raphael, 1837-1923
Publicado 1886