@book{561615,
	author = {Christopherson, Robert W.},
	title = {Geosystems :},
	publisher = {Addison Wesley Longman,},
	year = {2001},
	address = {[S.l.] :},
	url = {http://www.amazon.com/exec/obidos/ASIN/0130613452/chopaconline-20}
}