@book{33359,
	author = {Boullon, Roberto C. and Molina E., Sergio.},
	title = {Un nuevo tiempo Libre :},
	publisher = {Trillas,},
	year = {1991.},
	series = {Serie Trillas turismo},
	address = {Mexico :},
	edition = {2a. ed.},
	note = {Incluye indices.}
}