Carvan, John, author
LBC Information Services Holmes Beach, 1997
Buku Teks
Finn, Paul, author
Oxford University Press, 1987
Buku Referensi
Cranston, Ross, author
Oxford University Press, 1987
Buku Teks
Waller, Louis, author
Butterworth, 1989
Buku Teks
Tracey, Richard R.S., author
Butterworth, 1975
Buku Teks