@book{671,
	author = {Spiegel, Murray R. and Hernandez Heredero, Rafael},
	title = {Estadística},
	publisher = {McGraw-Hill},
	year = {1991},
	address = {Madrid :},
	edition = {2a. ed.},
	url = {https://www.biblioeco.unsa.edu.ar/pmb/images/libros/15999.jpg}
}