The Helvetia area porphyry systems, Pima County, Arizona, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera
Anzalone, S.A., 1995, The Helvetia area porphyry systems, Pima County, Arizona, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera: Arizona Geological Society Digest 20, p. 436-441.
