Ziegler, David M.
Little, Brown, 1981
Buku Teks
Evera, Stephen van
[publisher not identified], [date of publication not identified]
Buku Teks
Schmitt, Michael N.
T.M.C. Asser Press, 2012
eBooks
Krasner, Stephen D.
Routledge , 2009
Buku Teks
Grob, Fritz
Yale University Press, 1949
Buku Klasik