@book{786,
	author = {Helfrich, Harold W.,},
	title = {The Environmental crisis.},
	publisher = {Yale University Press,},
	year = {1970; [c1970-71]},
	address = {New Haven,},
	note = {"Lectures which comprised a 1968-69 symposium on 'Issues in environmental crises' at the Yale University School of Forestry."}
}