Edited by Norbert Pachler; Ana Redondo
Routledge, 2007
Buku Teks SO
Ur, Penny
Cambridge University Press, 1999
Buku Teks SO
Coxon, Rosemary
Letts Educational, 1994
Buku Teks
Burton, Samuel Holroyd
Macmillan, 1995
Buku Teks
Hess, Natalie
Cambridge University Press, 2001
Buku Teks