edited by Richard Kostelanetz
United States International Communication Agency, 1982
Buku Teks SO
Forum Series, 1982
Buku Teks
edited by Don M. Wolfe
Hendrick House, 1955
Buku Teks SO
Stevenson, Burton Egbert
Henry Holt, 1942
Buku Referensi
edited by Charles Higham
Penguin Books, 1968
Buku Teks SO