@book{551,
	author = {Tokheim, Roger L.},
	title = {Schaum's outline of theory and problems of digital principles /},
	publisher = {Mcgraw-Hill,},
	year = {1988.},
	series = {Schaum's outlines.},
	address = {[S.l.] :},
	edition = {2 Sub ed.},
	url = {http://www.amazon.com/exec/obidos/ASIN/0070650128/chopacon}
}