Citazione Stile APA (7a Edizione)

(Earth Works Group (U.S. (1989). 50 simple things you can do to save the earth. Earthworks Press.

Citazione stile Chigago Style (17a edizione)

(Earth Works Group (U.S. 50 Simple Things You Can Do to Save the Earth. .Berkeley, CA: Earthworks Press, 1989.

Citatione MLA (9a ed.)

(Earth Works Group (U.S. 50 Simple Things You Can Do to Save the Earth. Earthworks Press, 1989.