Mark S. Lee, authror
Thomson, 2006
Buku Teks
Smith, Roger J., author
Longman, 2000
Buku Teks
Melville, L. W.
Sweet and Maxwell , 1972
Buku Teks
Llewelyn, David, author
Marshall Cavendish Business, 2010
Buku Teks
Ricketson, Sam, author
Butterworth, 1994
Buku Teks