@book{4140,
	author = {Pipkin, Bernard W. and Trent, Dee D.},
	title = {Geology and the environment /},
	publisher = {Cengage Learning,},
	year = {2010.},
	address = {[S.l.] :},
	edition = {6th ed.},
	url = {http://www.amazon.com/exec/obidos/ASIN/0538737557/chopaconline-20}
}