@book{13305,
	author = {Field, Barry C. and Field, Martha K.},
	title = {Environmental economics :},
	publisher = {McGraw-Hill,},
	year = {c2006.},
	address = {Boston :},
	edition = {4th ed.},
	url = {http://www.loc.gov/catdir/enhancements/fy0625/2005049561-d.html}
}