Artikel Jurnal
Miller, G. Tyler (George Tyler), 1931-, author
Thomson, Brooks/Cole, 2008
Buku Teks
United Nations Conference on Human Environment, 1972
Buku Teks
by Jay Lehr [and others]
McGraw-Hill, 2002
Buku Referensi
by Jay Lehr, Marve Hyman, Tyler E. Gass, William Seevers
McGraw-Hill, 2001
Buku Referensi