@book{57020,
	author = {Tokheim, Roger L},
	title = {Schaum's outline of theory and problems of digital principles. -- 3rd ed.},
	publisher = {McGraw-Hill},
	year = {1994},
	address = {New York:},
	edition = {3rd ed.},
	note = {Donated by Counsellor Kang'ombe}
}