Bagehot, Walter
Oxford University Press, 1977
Buku Teks
Lovell, Colin Rhys
Oxford University Press, 1962
Buku Teks
Amery, L.S., author
Oxford University Press, 1953
Buku Teks
Jennings, Ivor, Sir, 1903-1965, author
Hodder and Stoughton, 1979
Buku Teks
edited by Jeffrey Jowell and Dawn Oliver
Clarendon Press, 1994
Buku Teks