APA (7th ed.) Citation

The Earth Works Group. (1989). 50 simple things you can do to save the earth. Earth Works Press.

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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