Smith, David, editor
Macmillan, 1995
Buku Teks
Burke, Gill
Longman, 1981
Buku Teks
Sullivan, Michael
Harvester Wheatsheaf, 1994
Buku Teks
Steve J. Hothersall, Mike Maas-Lowit
Learning Matters Ltd., 2010
Buku Teks
Clarendon Press Oxford, 1989
Buku Teks