APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

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

MLA (9e ed.) Bronvermelding

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