Langen, Eugen.
A. W. Sijthoff , 1973
Buku Teks
Jessup, Philip Caryl, 1897-1986
Yale University Press, 1956
Buku Teks
Goode, Roy
Penguin Books, 2004
Buku Teks
Savage, Nigel
Butterworth, 1991
Buku Teks
Hewiit, Charles M.
Houghton Mifflin, 1962
Buku Teks