作者 | Geoffrey G. Kay / Robert E. Bugbee / J. Richard Wohler / Pennsylvania. Department of Environmental Resources / Talon Division of Textron / Sunbeam Equipment Corporation / PPG Industries Foundation / American Viscose Division of FMC. / Hughson Chemical Company / French Creek Valley Conservancy / Allegheny College (Meadville, Pa.) / Northwestern Pennsylvania Regional Planning and Development Commission / Appalachian Regional Commission |