Richmond, D.L., 1976, Soil survey of the Willcox area, Arizona - parts of Cochise and Graham Counties: U.S. Department of Agriculture, Soil Conservation Service, 76 p., 48 sheets, scale 1:20,000.
Richmond, D.L., 1971, General soil map, Cochise County, Arizona: U.S. Department of Agriculture, Soil Conservation Service, 52 p., 1 sheet, scale 1:500,000.
Raines, G.L., 1984, Preliminary map showing limonitic areas in the Silver City 1o x 2o quadrangle, Arizona and New Mexico: U.S. Geological Survey Miscellaneous Field Studies Map MF-1183-Q, 1 sheet, scale 1:250,000.
Pipkin, B.W., 1964, Clay mineralogy of the Willcox Playa and its drainage basin, Cochise County, Arizona: Tucson, University of Arizona, Ph.D. dissertation, 160 p.
Pine, G.L., 1963, Sedimentation studies in the vicinity of Willcox Playa, Cochise County, Arizona: Tucson, University of Arizona, M.S. thesis, 38 p.
Peirce, H.W., 1969, Salines, in Mineral and water resources of Arizona: Arizona Bureau of Mines Bulletin 180, p. 417-424.
O'Neill, A.J., and Thiede, D.S., 1982, National Uranium Resource Evaluation, Silver City quadrangle, New Mexico and Arizona: U.S. Department of Energy Report PGJ/F-131(82), 87 p., 14 microfiche, 18 sheets, scales 1:12,000, 1:24,000, 1:500,000.
Nations, J.D., and Landye, J.J., 1974, Cenozoic plant and animal fossils of Arizona [and Appendix A-D], in Smiley, T.L., Nations, J.D., Pewe, T.L., and Schafer, J.P., eds., Landscapes of Arizona - The geological story: Lanham, Md., University Press of America, p. 7-35, 428-479.
Meinzer, O.E., and Kelton, F.C., 1913, Geology and water resources of Sulphur Spring Valley, Arizona, with a section on Agriculture, by R.H. Forbes: U.S. Geological Survey Water-Supply Paper 320, 231 p., 2 sheets, scale 1:250,000.
Mann, L.J., White, N.D., and Wilson, R.P., 1978, Maps showing ground-water conditions in the Willcox area, Cochise and Graham Counties, Arizona - 1975: U.S. Geological Survey Water-Resources Investigations 78-0060 Open-File Report, 3 sheets, scale 1:125,000.