Elbow, Peter, author
iPublishing, 2010
Buku Teks
Lucas, Michael
Heinemann Educational Books, 1981
Buku Teks
Watcyn-Jones, Peter
Penguin books, 1993
Buku Teks
Iain Hay
McGraw-Hill , 2011
Buku Teks
Celce-Murcia, Marianne, author
Cambridge University Press, 2011
Buku Teks