Parrot, Martin
Cambridge University Press, 2003
Buku Teks
Thornburn, Scott, 1950-
Cambridge University Press, 2017
Buku Teks
Gorlewski, Julie A.
Sense, 2012
eBooks
Farrell, Thomas S.C.
Corwin Press, 2006
Buku Teks
Lucas, Michael
Heinemann Educational Books, 1981
Buku Teks