@book{188578,
	author = {Verba, Sidney. and Nie, Norman H.},
	title = {Participation in America :},
	publisher = {University of Chicago Press,},
	year = {1987, c1972.},
	address = {Chicago :},
	edition = {University of Chicago Press ed.},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/enhancements/fy0608/87010825-d.html}
}