@book{320,
	author = {Ary, Donald and Cheser Jacobs, Lucy},
	title = {Introducción a la investigación pedagógica},
	publisher = {McGraw-Hill Interamericana de México},
	year = {1989},
	address = {México, D.F.},
	edition = {2a ed},
	note = {Incluye índice de autores}
}