editor Frank N. Magill
Toppan Company, 1996
Buku Referensi
Brint, Michael, author
Westview Press, 1991
Buku Referensi
editors, Dermot Englefield, Gavin Drewry
Butterworth, 1984
Buku Referensi
Gallagher, Mary Elizabeth, author
Princenton University Press, 2005
Buku Teks
Jackson, W.A. Douglas, author
Prenciton-Hall , 1964
Buku Teks