Citazione Stile APA (7a Edizione)

Earth Works Group (Estados Unidos) & Earth Works Group. (1990). 50 simple things kids can do to save the earth. Andrews and McMeel.

Citazione stile Chigago Style (17a edizione)

Earth Works Group (Estados Unidos) e Earth Works Group. 50 Simple Things Kids Can Do to Save the Earth. Kansas City: Andrews and McMeel, 1990.

Citatione MLA (9a ed.)

Earth Works Group (Estados Unidos) e Earth Works Group. 50 Simple Things Kids Can Do to Save the Earth. Andrews and McMeel, 1990.