Bugajski, Janusz, author
Westview Press, 1989
Buku Teks
Schmitt, Michael N., author
T.M.C. Asser Press, 2012
eBooks
edited by Stephen White, Judy Batt and Paul G. Lewiss
Macmillan, 1993
Buku Teks
Seton-Watson, Hugh, author
Methuen , 1950
Buku Teks
Westview Press , 1990
Buku Teks