Helvetia, Arizona, porphyry copper test site report, Sect. 5, in Paley, H.N., ed., The joint NASA/Geosat test case project, Final report, Part 2, V. 1

Abrams, M.J., Sadowski, Ray, and Prost, G.L., 1984, Helvetia, Arizona, porphyry copper test site report, Sect. 5, in Paley, H.N., ed., The joint NASA/Geosat test case project, Final report, Part 2, V. 1: American Association of Petroleum Geologists, p. 5.1-5.78.