Cheshire, 1974
Buku Teks
edited by Gordon Greenwood and Norman Harper
F.W. Chesire, 1968
Buku Teks
Lovering, T.S.
Prentice-Hall, 1943
Buku Teks
Lenczowski, George
Cornell University Press, 1956
Buku Teks
Edited by Kajima Institute of International Peace.
Japan Times, 1971
Buku Referensi