U.S.Bureau of Mines Mineral Commodity Summaries,1991 - - Washington - EEUU U.S.Bureau of Mines.U.S.Geological Survey 1991 - 196p. Bordeau y Negro 28cm - . ISBN: no Subjects--Topical Terms: --Industria Minera--Mineria--Recursos Naturales--Energetica--Estadisticas----Geologia