Schaller, Michael, author
Oxford University press, 1979
Buku Teks
Borg, Dorothy
Macmillan, 1947
Buku Teks
Krasner, Stephen D.
Princeton University Press, 1978
Buku Teks
Langdon, Robert M., author
Littlefield Adams, 1961
Buku Teks
Goldstein, Steven M., author
Polity Press, 2015
Buku Teks