(Earth Works Group (U.S. (1989). 50 simple things you can do to save the earth. Earthworks Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र(Earth Works Group (U.S. 50 Simple Things You Can Do to Save the Earth. .Berkeley, CA: Earthworks Press, 1989.
एमएलए (9वां संस्करण) प्रशस्ति पत्र(Earth Works Group (U.S. 50 Simple Things You Can Do to Save the Earth. Earthworks Press, 1989.
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