Coggle, Paul, author
Teach Youeself Books, 1991
Buku Teks
Bhatia, Tej K., author
Routledge, 2000
Buku Teks
Peck, Anthony
MacMillan,, 1995
Buku Teks
Graham, Gaelle, author
Hodder & Stoughton, 1991
Buku Teks
Bruce, R. Robert, author
Hodder & Stoughton, 1994
Buku Teks