Bremmelen, R.W. Van
Martinus Nijhoff, 1970
Buku Referensi
Toynbee, Arnold J., author
Oxford University Press , 1948
Buku Referensi
edited by George A. Vanasse
Academic Press, 1981
Buku Teks
Owen, George E., author
Harper and Row, 1967
Buku Teks
Katz, William A., 1924-, author
McGraw-Hill, 1987
Buku Teks