Gaya APA
Enger, E, D., Smith, B, F. (2004).
Environmental Science : A Study of Interrelationships .
Amerika Serikat:
McGraw - Hill.
Gaya MLA
Enger, Eldon, D.., Smith, Bradley, F..
"Environmental Science : A Study of Interrelationships".
Amerika Serikat:
McGraw - Hill,
2004.
Text.