Cita APA (7a ed.)

Cunningham, W. P., & Cunningham, M. A. (2012). Environmental science: A global concern (12th ed.). McGraw-Hill Companies, Inc.

Cita Chicago Style (17a ed.)

Cunningham, William P., y Mary Ann Cunningham. Environmental Science: A Global Concern. 12th ed. New York: McGraw-Hill Companies, Inc, 2012.

Cita MLA (9a ed.)

Cunningham, William P., y Mary Ann Cunningham. Environmental Science: A Global Concern. 12th ed. McGraw-Hill Companies, Inc, 2012.