Gaya APA

Enger, E, D., Smith, B, F. (2004). Environmental science : a study of interrelationships (Edisi 9). New York: Higher Education.

Gaya MLA

Enger, Eldon, D.., Smith, Bradley, F.. "Environmental science : a study of interrelationships". Edisi 9 New York: Higher Education, 2004. Text.