Areas in Arizona with elevated concentrations of uranium, in Spencer, J.E., ed., Radon in Arizona
Spencer, J.E., Shenk, J.D., and Duncan, J.T., 1993, Areas in Arizona with elevated concentrations of uranium, in Spencer, J.E., ed., Radon in Arizona: Arizona Geological Survey Bulletin 199, Plate 1, scale 1:1,000,000.