@book{1890,
	author = {Gopal, Madan},
	title = {Digital Control Engineering.},
	publisher = {John Wiley & Sons,},
	year = {1989.},
	address = {[S.l.] :},
	url = {http://www.amazon.com/exec/obidos/ASIN/0852263082/chopaconline-20}
}