Earth Works Group (Estados Unidos) & Earth Works Group. (1990). 50 simple things kids can do to save the earth. Andrews and McMeel.
Chicagoスタイル(17版)引用形式Earth Works Group (Estados Unidos) , Earth Works Group. 50 Simple Things Kids Can Do to Save the Earth. Kansas City: Andrews and McMeel, 1990.
MLA(9版)引用形式Earth Works Group (Estados Unidos) , Earth Works Group. 50 Simple Things Kids Can Do to Save the Earth. Andrews and McMeel, 1990.
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