Child, John, author
George Allen and Unwin, 1969
Buku Teks
Courtis, John
Arcan , 1992
Buku Teks
Fulmer, Robert M., author
Macmillan, 1974
Buku Teks
Regester, Michael, author
Kogan Page, 1997
Buku Teks
Lockyer, K.G., author
Sir Isaac Pitman and Sons, 1969
Buku Teks