@book{677,
	author = {Spiegel, Murray R. and Gómez Espadas, José Luis},
	title = {Teoría y problemas de estadística},
	publisher = {McGraw-Hill},
	year = {1970},
	address = {México :},
	url = {https://www.biblioeco.unsa.edu.ar/pmb/images/libros/16005.jpg}
}