| Reference | {Deposit:: F1 < TABOR, 1969, U.S. MAILMAN, BALWIN, IA, ORAL COMMUNICATION TO A. V. HEYL.}{Deposit:: HEYL, A. V., FIELD NOTES}{Deposit:: F3 < HEYL, A. V., AND WEST, W. S., 1982, OUTLYING MINERAL OCCURRENCES RELATED TO THE UPPER MISSISSIPPI VALLEY MINERAL DISTRICT, WISCONSIN, IOWA, ILLINOIS, AND MINNESOTA: ECONOMIC GEOLOGY, V. 77, P. 1803-1817.} |