Vincent, Mark
London University, 2003
Buku Teks
Speight, Kathleen
The English Universities Press, 1957
Buku Teks
Aitchison, Jean, 1938-
Contemporary Books, 2008
Buku Teks
Schild, Herbert
McGraw-Hill, 1997
Buku Teks
Bride, Mac
Hodder Headline Plc., 1995
Buku Teks