Finch, D. M. (1992). Threatened, endangered, and vulnerable species of terrestrial vertebrates in the rocky mountain region. United States Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station.
Chicago-referens (17:e uppl.)Finch, Deboran M. Threatened, Endangered, and Vulnerable Species of Terrestrial Vertebrates in the Rocky Mountain Region. Fort Collins, Colorado: United States Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1992.
MLA-referens (9:e uppl.)Finch, Deboran M. Threatened, Endangered, and Vulnerable Species of Terrestrial Vertebrates in the Rocky Mountain Region. United States Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1992.