@book{57222,
	author = {Hedrick, Terry E. and Bickman, Leonard,},
	title = {Applied research design :},
	publisher = {Sage Publications,},
	year = {c1993.},
	series = {Applied social research methods series ;},
	address = {Newbury Park :},
	url = {http://www.loc.gov/catdir/enhancements/fy0655/92037330-d.html}
}