| Reference | U. S. GEOLOGICAL SURVEY, U. S. BUREAU OF RECLAMATION, AND SOUTH DAKOTA GEOLOGICAL SURVEY, 1975 , MINERAL AND WATER RESOURCES OF SOUTH DAKOTA, SOUTH DAKOTA GEOLOGICAL SURVEY BULLETIN 16 { BIENIEWSKI, C. L., AND MCGREGOR, D. J., 1965 , THE MINERAL INDUSTRY OF SOUTH DAKOTA IN 1963 , SOUTH DAKOTA GEOLOGICAL SURVEY MINERALS REPORT 11 |