Allsop, Jake
Cassell, 1981
Buku Teks
McArthur, Thomas Burns, author
Oxford University Press, 1983
Buku Teks
Ewer, J.R.
Longman, 1969
Buku Teks
Burton, Samuel Holroyd, author
Macmillan, 1995
Buku Teks
Blundell, Jon, author
Oxford University Press, 1982
Buku Teks