United Nations, 1983
Buku Teks
Edited by Ben G. Goedegebuure; Humberto R. Arango Sales; Gilberto Sotolongo Aguilar
Elsevier, 1991
Buku Teks
Asia Publishing House , 1964
Buku Teks
Schwarz, A.F.
Academic Press, 1987
Buku Teks
Boulden, James B., author
McGraw-Hill, 1975
Buku Teks