@book{68651,
	author = {National Society for the Study of Education. and Henry, Nelson B.},
	title = {Learning and instruction.},
	publisher = {[National Society for the Study of Education] distributed by the University of Chicago Press},
	year = {1950.},
	series = {Yearbook of the National Society for the Study of Education, 49th, pt. 1},
	address = {Chicago}
}