edited by R.R. Betts
Royal Institute of International Affairs, 1950
Buku Teks
Tinbergen, Jan, 1903-
Yale University Press, 1964
Buku Teks
Rice, Tamara Talbot
Praeger, 1965
Buku Teks
Basu, S.K.
Asia Publishing House, 1967
Buku Teks
Rodriguez, Mario
Prentice-Hall, 1965
Buku Teks