@book{15048,
	author = {MacKenzie, Ossian. and Christensen, Edward L. and American Council on Education.},
	title = {Correspondence instruction in the United States},
	publisher = {McGraw-Hill},
	year = {[1968]},
	series = {The Carnegie series in American education},
	address = {New York},
	note = {Study sponsored by the American Council on Education and the National Commission on Accrediting.}
}