Lecercle, Jean-Jacques, author
Routledge, 1994
Buku Teks
Walker, William, author
Cambridge University Press, 2009
eBooks
Knowles, Murray, author
Routledge, 1996
Buku Teks
Cambridge University Press, 1997
eBooks
Britton, James N.
Cassell Educational Limited, 1993
Buku Teks