@book{21258,
	title = {Global english academy},
	publisher = {Océano},
	year = {2006},
	address = {Barcelona},
	note = {Tiene 3 niveles: Beginners (tomos 1.1 al 1.4), Intermediate (tomos 2.1 al 2.4) y Advanced (tomos 3.1 al 3.4)}
}