Simons, F.S., Theobald, P.K., Tidball, R.R., Erdman, J.A., Harms, T.F., Griscom, A., and Ryan, G.S., 1987, Mineral resources of the Needles Eye Wilderness Study Area, Gila County, Arizona, Chapter B, in Mineral resources of Wilderness Study Areas - southeastern Arizona: U.S. Geological Survey Bulletin 1703-B, p. B1-B7, 1 sheet, scale 1:24,000.
