@book{633,
	author = {Girard, Bernard and Meléndez, Esperanza},
	title = {El modelo google},
	publisher = {Grupo Editorial Norma},
	year = {2007},
	address = {Bogotá :},
	url = {https://biblioeco.unsa.edu.ar/pmb/images/libros/El modelo google-l118990.jpg}
}