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- [3] PROPOSALS, ABOLISHMENTS, AND CHANGING STANDARDS FOR UNITED-STATES NATIONAL-PARKS HISTORIAN, 1991, 54 (01): : 49 - 64
- [5] PARTICULATE MONITORING AT UNITED-STATES NATIONAL-PARKS USING PIXE NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 1987, 22 (1-3): : 289 - 295
- [10] PROTECTING UNITED-STATES NATIONAL-PARKS - INNOVATIVE MEASURES FOR CHALLENGING TIMES ENVIRONMENT, 1990, 32 (01): : 18 - 19