Spencer, E. W. (2003). Earth science: Understanding environmental systems. McGraw - Hill.
Chicago Style aipamenaSpencer, Edgar W. Earth Science: Understanding Environmental Systems. Boston: McGraw - Hill, 2003.
MLA aipamenaSpencer, Edgar W. Earth Science: Understanding Environmental Systems. McGraw - Hill, 2003.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.