Bittker, Boris I.
Federal Tax Press, 1968
Buku Teks
Eljinah Anderson, editor ; Dougkas S. Massey, editor
Ruseel sage foundation, 2001
Buku Teks SO
United Nations, 1970
Buku Teks
Iwata, Kazumasa
Tokyo Dept. of Social and International Relations,University of Tokyo, 1994
Buku Teks
Tobias Soebekti
Indiana University, 1964
Buku Teks