Fitzgerald, C.P.
Cresset Press, 1958
Buku Teks
Rosinger, Lawrence K.
Princeton, 1944
Buku Teks
Eberhard, Wolfram
Franche Ag, 1948
Buku Teks
Smedley, Agnes
Vanguard Press, 1938
Buku Teks
A.K.P. Mochtan, editor
Centre for Strategic and International Studies, 1992
Buku Teks