Spencer, E. W. (2003). Earth science: Understanding environmental systems. McGraw - Hill.
Chicago Style (17th ed.) CitationSpencer, Edgar W. Earth Science: Understanding Environmental Systems. Boston: McGraw - Hill, 2003.
MLA (9th ed.) CitationSpencer, Edgar W. Earth Science: Understanding Environmental Systems. McGraw - Hill, 2003.
Advarsel: Disse citationer er muligvist ikke 100% nøjagtige.