@book{27,
	author = {Cunningham, William P. and Cunningham, Mary Ann.},
	title = {Environmental science :},
	publisher = {McGraw-Hill,},
	year = {c2003.},
	address = {Dubuque, Iowa :},
	edition = {7th ed. /},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/description/mh021/2001044744.html}
}