Geologic map of the Ontonagon and part of the Wakefield 30' X 60' quadrangles, Michigan; a digital representation of Map I-2499 (1995) - Cannon, W.F.; Nicholson, S.; Woodruff, L.; Hedgman, C.; Schultz, K.J.; Pimley, S.G. (Open-File Report, 2001)