APA استشهاد

Cunningham, W. P. a. C. (2011). Principles of environmental science: Inquiry & applications (6th ed.). McGraw-Hill.

استشهاد بنمط شيكاغو

Cunningham, William P. and Cunningham. Principles of Environmental Science: Inquiry & Applications. 6th ed. New York: McGraw-Hill, 2011.

MLA استشهاد

Cunningham, William P. and Cunningham. Principles of Environmental Science: Inquiry & Applications. 6th ed. McGraw-Hill, 2011.