Kirkpatrick, Larry D.
Thomson, Brooks, 2007
Buku Teks
edited by Sidney Mailick; The United Nations Institute for Training and Research
Anchor Press, 1974
Buku Teks
edited by Yufan Hao and Guocang Huan
Phanteon Books, 1989
Buku Teks SO
Simpson, George Gaylord
Harcourt Brace & World, 1964
Buku Teks
Kirkpatrick, Larry D.
Brooks/Cole Cengage Learning, 2010
Buku Teks SO