@book{227047,
	author = {Palmer, James E. and Perlman, David E. and e-libro, Corp.},
	title = {Introducción a los sistemas digitales},
	publisher = {McGraw-Hill Interamericana},
	year = {1995.},
	address = {México},
	url = {http://site.ebrary.com/lib/pucpr/Doc?id=10436640}
}