@book{15354,
	author = {Conrad, Jon M. and Clark, Colin Whitcomb,},
	title = {Natural resource economics :},
	publisher = {Cambridge University Press,},
	year = {1987.},
	address = {Cambridge [Cambridgeshire] ;},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/samples/cam034/87011582.html}
}