Ulrich, G.E., Holm, R.F., and Wolfe, E.W., 1989, Second-day field trip: San Francisco volcanic field, in Ulrich, G.E., and others, Excursion 5A: Miocene to Holocene volcanism and tectonism of the southern Colorado Plateau, Arizona, in Chapin, C.E., and Zidek, J., eds., Field excursions to volcanic terranes in the western United States, Volume I: Southern Rocky Mountain region, IAVCEI General Assembly, Santa Fe, New Mexico, USA, June 25 - July 1, 1989: New Mexico Bureau of Mines and Mineral Resources Memoir 46, p. 10-21.
