Gaya APA

Cunningham, W, P., Cunningham, M, A. (2006). Principles of Environmental Science : Inquiry & Applications (3th ed.) . New York: McGraw-Hill.

Gaya MLA

Cunningham, William, P.., Cunningham, Mary, Ann. "Principles of Environmental Science : Inquiry & Applications (3th ed.)". New York: McGraw-Hill, 2006. Text.