edited by Ulli Beier
University of Queensland Press, 1980
Buku Teks SO
edited by Charles Higham
Penguin Books, 1968
Buku Teks SO
Forum Series, 1982
Buku Teks
Itule, Bruce D.
McGraw-Hill, 1994
Buku Teks
edited by Richard Kostelanetz
United States International Communication Agency, 1982
Buku Teks SO