McLoughlin, J., author
Manchester University Press, 1972
Buku Teks
Redmond, Peter W.D., author
Macdonald and Evans, 1965
Buku Teks
Lydall, Harold
Oxford University Press, 1984.
Buku Teks
Russell, Bertrand, 1872-1970, author
George Allen & Unwin Ltd, 1949
Buku Teks
Longman Cheshire, 1991
Buku Teks