Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

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