edited by Peter Taylor-Gooby
Oxford University Press, 2013
Buku Teks
Kay, Adrian.
Edward Elgar, 2006
Buku Teks SO
Boyes, William J.
South Western Publishing, 1984
Buku Teks SO
Smith, Kevin
Westview Press, Boston, Massachusetts : Credo Reference, 2013
Buku Teks SO
Kurihara, Kenneth K.
W.W. Nortorn, 1950
Buku Teks