National park system [electronic resource] : hearing before the Subcommittee on Public Lands, Reserved Water, and Resource Conservation of the Committee on Energy and Natural Resources, United States Senate, Ninety-ninth Congress, first session, on the presentation of the Conservation Foundation's report, "National Parks for a new generation," presentation of the National Parks Service Director Mott's 12 points for guiding the national parks, and other park related issues, July 18, 1985.