Cincotta, R.P., and R. Engelman. 2000. Nature's Place—Human Population and the Future of Biological Diversity. Population Action International. Washington, DC.

Cooperrider, Allen. 1991. In "Landscape Linkages and Biodiversity," Wendy Hundson, ed. Defenders of Wildlife. Washington, DC.

Crumpacker, D.W., and S.W. Hodge. 1988. "Representation of major terrestrial and wetland ecosystems in the National Park System of the United States and comparison with other U.S. national land management systems." In New Parks: New Promise. National Parks Conservation Association. Washington, DC.

Dottavio, Dominic. (ed.) 1990. "Recommendations from a workshop on protecting diversity in the national parks." National Park Service. Washington, DC.

Knapp, R.A., and K.R. Matthews. 2000. "Non-native fish introductions and the decline of the mountain yellow-legged frog within protected areas." Conservation Biology 14:428-438.

Milstein, M. 1999. "Yellowstone Park stumbles under the weight of alien species." Billings Gazette. October 11.

National Parks Conservation Association. 1988. "New Parks: New Promise." National Parks Conservation Association. Washington, DC.

National Parks Conservation Association. 1989. "National Parks: From Vignettes to a Global View." National Parks Conservation Association. Washington, DC.

National Parks Conservation Association. 1999. "Strategic Action Plan." National Parks Conservation Association. Washington, DC.

National Parks Conservation Association. 2000. "Parks in the 21st Century Initiative." National Parks Conservation Association. Washington, DC.

National Park Service. 1991. "National parks for the 21st Century—The Vail Agenda." National Park Service. Washington, DC.

National Park Service. 1991. "Natural Resources Management Guideline (NPS-77)." National Park Service. Washington, DC.

National Park Service. 1996. "Preserving Our Natural Heritage: A Strategic Plan for Managing Invasive Nonnative Plants on National Park Service Lands." National Park Service. Washington, DC.

National Park Service. 1999. "Natural resource challenge: The National Park Service's action plan for preserving natural resources." National Park Service, Washington, DC.

National Park Service. 2001. "Management Policies." National Park Service. Washington, DC.

Newmark, William D. 1987. "A land-bridge perspective on mammal extinctions in western North American parks." Nature 325:430.

Noss, Reed. 1990. "What can wilderness do for biodiversity?" In Preparing to Manage Wilderness in the 21st Century. Patrick C. Reed, ed. Southeastern Forest Experiment Station. Asheville, NC.

Noss, Reed and Robert L. Peters. 1995. "Endangered Ecosystems: A Status Report on America's Vanishing Habitat and Wildlife." Defenders of Wildlife. Washington, DC.

Riebesame, William E. (ed.). 1997. Atlas of the New West. W.W. Norton & Company. New York.

Riccardi, A., and J. B. Rasmussen. 1999. "Extinction rates of North American freshwater fauna." Conservation Biology 13:1220-1222.

Sellars, Richard W. 1997. Preserving Nature in the National Parks. Yale University Press. New Haven, CT.

Soule, M.E., and J. Terborgh. 1999. Continental Conservation—
Scientific Foundations of Regional Reserve Networks. Island Press. Washington, DC.

Stein, B.A., L.S. Kutner, and J.S. Adams (eds.). 2000. Precious Heritage—The Status of Biodiversity in the United States. Oxford University Press. Oxford.

Toops, C. 1999. "By leaps and bounds." National Parks. September, pp. 30-33.

Wilcove, D., D. Rothstein, J. Dubow, A. Phillips and E. Losos. 1998. "Quantifying threats to imperiled species in the United States." Bioscience 48: 607-615.

World Wildlife Fund et al. 2000. Freshwater Ecoregions and Terrestrial Ecoregions of North America. Island Press. Covelo, CA. (2 volumes)