@book{52796,
	author = {Torretti, Roberto., and e-libro, Corp.},
	title = {Relatividad y espaciotiempo},
	publisher = {RIl. editores,},
	year = {2003.},
	address = {Santiago de Chile :},
	url = {https://elibro.net/ereader/politecnicointernacional/67936}
}