@book{94394,
	author = {Leyva Hernández, Gerardo.},
	title = {La comercialización de frijol en el Estado de Zacatecas :},
	publisher = {El autor,},
	year = {2007},
	address = {Chapingo, Méx. :},
	url = {http://10.13.5.2/tesis/105989.pdf}
}