The Ministry of Foreign Affairs of the German Democratic Republic, 1961
Buku Teks
Ath-Thawra Publications, 1972
Buku Teks
Altwaijri, Abdulaziz Othman
ISESCO , 1997
Buku Teks
Roche, John P.
McGraw-Hill, 1954
Buku Teks
Appleby, Paul H., author
Louisiana State University Press, 1952
Buku Teks