Skinner, B. J., 1989, Mineral Resources of North America, pp. 575 - 584, in: A. W. Bally, & A. R. Palmer (eds.), The Geology of North America—An Overview, The Geology of North America, vol. A, Geological Society of America, Boulder, CO.
State-based Resources
Frank, D. G., A. R. Wallace, & J. L. Schneider, 2010, Western Mineral and Environmental Resources Science Center—providing comprehensive earth science for complex societal issues, US Geological Survey Circular 1363, 32 pp.