Artikel Jurnal
Chusnul Mar`iyah
Department of Government, The University of Sydney, 1998
Buku Teks
Kaiser, Edward John
Buku Teks
Chapin, F. Stuart (Francis Stuart), 1916-
University of Illinois Press, 1979
Buku Teks
Robert, Neal Alison
Macmillan, 1972
Buku Teks