@book{119493,
	author = {Calleja Medel, Gilda. and Tirado Zabala, Carlos.},
	title = {Cómo dominar la matematica comercial rápidamente},
	publisher = {Editorial Playor},
	year = {c1990.},
	series = {Como Dominar},
	address = {Madrid},
	edition = {5a ed.},
	note = {Title on spine: Aritmética comercial.}
}