2"Budget Justification And Annual Performance Plan Fiscal Year2003 National Park Service", The Department of Interior,2003.
3"National Park Service Statistical Abstract 2002", National Park Service, Public Use Office,2003.
4Lary M. Dilsaver, "America's National park System: The Critical Documents" Rowman & Littlefield Publishers, 1994.
5Harlan D. Unrau, G. Frank Williss, "Expansion of the National Park Service in the 1930s", Natiknal Park Service,Denver Service Center, 1983.
6United States Code,Governent Printing Office,2000.
7Code of Federal Regulation, Government Printing Office,2000.
8Federal Register, Government Printing Office,2000.
9Sellars, Richard W. Preserving Na ture in the Natitional Parks. Yale University Press. 1997.
10Cole,David N.;Stankey,George H.1998.Historical development of Limits of Acceptable Change:conceptual clarifications and possible extensions—In: McCool.Stephen F.;Cole,David N.,comps.1998.Proceedings:Limits of Acceptable Change and related planning processes:progress andfuture directions;processes:progress1997 May 20-22;Missoula,MT.Gen.Tech. RepINT—GTR-371.ogden,UT:US.Department of Agriculture,Forest Service,Rocky Mountain Research Station.5—9.