Gillenwater, M. (1969) "Outdoor education: a coat of many colors." Peabody J. of Education46 (March).
2.
International Joint Commission on Air Pollution ( 1960) Report. The United States and Canada on the Pollution of the Atmosphere in the Detroit River AreaWashington, D.C. and Ottawa.
3.
Michael, D. (1970) The Unprepared Society. New York: Basic Books.
4.
Stapp, W. et al. (1970) "The concept of environmental education." Education Digest35 (March): 8-10.
