Roy, Robert H., author
John Hopkins Press, 1958
Buku Teks
Wardana Sulistiono, author
Fakultas Hukum Universitas Indonesia, 2016
UI - Skripsi (Membership)
Zeitlin, Irving M., author
Polity Press, 2007
Buku Teks
Trevor-Roper, H.R.
New York Harper & Row 1957
Buku Teks
Shepperd, William R., author
Barnes and Noble, 1959
Buku Referensi