Lunney, glynn, author
West, 2010
Buku Teks
Dine, Janet, author
Blackstone Press, 1998
Buku Referensi
Stone, Richard, author
Blackstone Press, 1996
Buku Referensi
Macintryre, Ewan, author
Blackstone Press, 1998
Buku Referensi
Tracey, Richard R.S., author
Butterworth, 1975
Buku Teks