@book{49049,
	author = {Horton, Paul B. and Horton, Robert L.},
	title = {Programmed learning aid for introductory sociology /},
	publisher = {Learning Systems,},
	year = {c1971.},
	series = {Irwin programmed learning aid series},
	address = {Homewood, Ill. :},
	note = {Includes index.}
}