Cita APA (7th ed.)

Enger, E. D., & Smith, B. F. (2004). Environmental science: A study of interrelationships (Ninth edition.). McGraw-Hill Higher Education.

Cita Chicago (17th ed.)

Enger, Eldon D., i Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. Ninth edition. Boston: McGraw-Hill Higher Education, 2004.

Cita MLA (8th ed.)

Enger, Eldon D., i Bradley Fraser Smith. Environmental Science: A Study of Interrelationships. Ninth edition. McGraw-Hill Higher Education, 2004.