@book{4914,
	author = {Schain, Robert L. and Polner, Murray},
	title = {Obtención y empleo de medios de enseñanza económicos y gratuitos},
	publisher = {UTEHA},
	year = {1968},
	series = {Manual UTEHA breve. Educación},
	address = {México, D.F.}
}