Citazione Stile APA (7a Edizione)

Cunningham, W. P., & Cunningham, M. A. Principles of Environmental Science (9th ed.). Unknown.

Citazione stile Chigago Style (17a edizione)

Cunningham, William P., e Mary Ann Cunningham. Principles of Environmental Science. 9th ed. Unknown: Unknown.

Citatione MLA (9a ed.)

Cunningham, William P., e Mary Ann Cunningham. Principles of Environmental Science. 9th ed. Unknown.