SOUTH DAKOTA SCHOOL OF MINES BULL 1 1888 P 141CUMMINGS J B REPT OF S DAK STATE PLANNING BOARD 1936 TUNGSTEG IN SOUTH DAKOTA P 10 AND 26GEOL SURVEY BULL NO 380 1909 P 152SOUTH DAKOTA SCHOOL OF MINES BULL 17 1937 P 140 141SOUTH DAKOTA SCHOOL OF MINES BULL 12 1918 P 56 58SOUTH DAKOTA SCHOOL OF MINES BULL 10 1914 P 220U S BUREAU OF MINES INFO CIRC 7707 P 48