एपीए उद्धरण

The Earth Works Group. (1989). 50 simple things you can do to save the earth. Berkeley, CA: Earthworks Press.

शिकागो स्टाइल उद्धरण

The Earth Works Group. 50 Simple Things You Can Do to Save the Earth. Berkeley, CA: Earthworks Press, 1989.

एमएलए उद्धरण

The Earth Works Group. 50 Simple Things You Can Do to Save the Earth. Berkeley, CA: Earthworks Press, 1989.