Abdullah Saleh
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 1993
UI - Laporan Penelitian
Snyder, Louis L.
Van Nostrand Company, 1958
Buku Teks SO
Esposito, Vincnet
Praeger, 1965
Buku Teks SO
La Fargue, Thomas Edward
Stanford University Press, 1937
Buku Teks SO
Falls, Cyril, 1888-1971
G.P. Putnam's Sons, 1959
Buku Teks SO