Ernest
Kogan Page , 1995
Buku Teks
Bowers, John, 1956-, author
Blackstone Press, 1996
Buku Teks
Jefferson, Michael
Cavendish Publishing , 1994
Buku Teks
Sandys-Winsch, Godfrey, author
Shaw & Sons, 1993
Buku Teks
edited by David Nice
Councils and Education Press, 1986
Buku Teks