@book{8107,
	author = {Alencar, Marcelo S., and Rocha, Valdemar C. da,},
	title = {Communication systems },
	publisher = {Springer,},
	year = {c2005.},
	address = {New York :},
	url = {http://www.loc.gov/catdir/enhancements/fy0663/2005049937-d.html}
}