Riker, T.W.
Oxford University Press , 1931
Buku Teks
MacNair, Harley Farnsworth
D.van Nostrand Company,Inc., 1955
Buku Teks
MacNair, Harley Farnsworth
D.van Nostrand Company,Inc., 1950
Buku Teks
Botzaris, Notis
Librairie E. Droz, 1962
Buku Klasik
Stoyan, P. B.
Foreign Policy Association, 1940
Buku Teks