Artikel Jurnal
Koupelis, Theo, author
Jones & Bartlett learning, 2011
Buku Teks
Steinby, Torsten, author
Government, 1971
Buku Teks
Lancaster, Carol, author
Brooking Institution Press, 2005
Buku Teks
Wilson, Amrit
Pluto Press ; Winchester, MA, USA : Distributed in the USA by Unwin Hyman, 1989
Buku Teks