7Sellars, Richard W. Preserving Na ture in the Natitional Parks. Yale University Press. 1997.
8Cole,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.
9Fressell,Sidney S,Jr.；Recreational Use of Campsites in the Quetico—Superior Canoe Country.St.Paul,MN:University Minnesota；1963 Dissertation.
10Clark,Roger N,George H.Stankey,The Recreation Opportunity Spectrum A Framework for Planning,Management and Research,US Department of Asriculture Forest Service,Pacific Northwest Forest and Range Experiment Station,General Technical Report PNW98,December 1979.
