Bell, F. G. (2007). Basic enviornmental and engineering geology. Whittles Publishing.
Chicago Style aipamenaBell, F G. Basic Enviornmental and Engineering Geology. U. K: Whittles Publishing, 2007.
MLA aipamenaBell, F G. Basic Enviornmental and Engineering Geology. Whittles Publishing, 2007.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.