| Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 288 Galbraith, F.W. & D.J. Brennan (1959), Minerals of AZ: 36. Needham, A.B. & W.R. Storms (1956), Investigation of Tombstone district manganese deposits, Cochise Co., Arizona, US Bur. Mines rept. Inv. 5188 Romslo, T.M. & S.F. Ravitz (1947), Arizona manganese-silver ores, US Bur. Mines Rept. Inv. 4097 Rasor, C.A. (1939), Manganese mineralization at Tombstone, AZ, Econ.Geol.: 34: 790-803 Butler, B.S., et al (1938b), Geology and ore deposits of the Tombstone district, AZ, AZ Bur. Mines Bull. 143 |