Rich, P. E., & Tussing, A. R. (1973). The national park system in Alaska: An economic impact study. Institute of Social, Economic and Government Research, University of Alaska; [distributed by the University of Washington Press.

Rich, Pamela E., and Arlon R. Tussing. The National Park System in Alaska: An Economic Impact Study. [College]: Institute of Social, Economic and Government Research, University of Alaska; [distributed by the University of Washington Press, 1973.

Rich, Pamela E., and Arlon R. Tussing. The National Park System in Alaska: An Economic Impact Study. Institute of Social, Economic and Government Research, University of Alaska; [distributed by the University of Washington Press, 1973.