The Empire Mountains, Pima County, Arizona, in Heindl, L.A., ed., Southern Arizona Guidebook II, combined with the 2nd annual Arizona Geological Society Digest
Galbraith, F.W., 1959, The Empire Mountains, Pima County, Arizona, in Heindl, L.A., ed., Southern Arizona Guidebook II, combined with the 2nd annual Arizona Geological Society Digest: Arizona Geological Society, p. 127-133.