@book{1978,
	author = {Johnson, David W. and Johnson, Roger T.},
	title = {Aprender juntos y solos :},
	publisher = {Aique,},
	year = {1999.},
	series = {Carrera Docente},
	address = {Buenos Aires :},
	edition = {1ª ed.},
	note = {Incorpora bibliografía.}
}