Guset, Harry, author
Macmillan, 1989
Buku Teks
Grant, Glen Nolan, author
Tuttle, 2009
Buku Teks
Grant, Glen Nolan, author
Tuttle, 2009
Multimedia
Birley, Sue, author
Financial Times Prentice Hall, 2000
Buku Teks
Watson, John, author
Macmillan, 1990
Buku Teks