Wyllie, M.R.J.
Academic Press, 1963
Buku Teks
Marmor, Andrei, author
Oxford University Press, 1995
Buku Teks
Pearce, D. C.
Butterworth, 1998
Buku Teks
Laski, Harold J., author
George Allen and Unwin, 1949
Buku Teks
Cote, Piere-Andre
Les Editions Yvon Blais,Inc., 1991
Buku Teks