Citazione APA

Enger, E. D., & Smith, B. F. (2004). Environmental science: A study of interrelationships (9th ed.). Mc Graw hill.

Stile di citazione Chicago

Enger, Eldon D., e Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. 9th ed. Boston: Mc Graw hill, 2004.

Citazione MLA

Enger, Eldon D., e Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. 9th ed. Mc Graw hill, 2004.