editor, David M. John [and others]
Cambridge University Press, 2011
Buku Referensi
John, D. M.
Cambridge University Press, 2011
Multimedia
Reynolds, C.S., author
Cambridge University Press, 1993
Buku Teks
Mason, C.F.
Pearson Education ltd, 1996
Buku Teks
Edited by Craig D. Sandgren
Cambridge University Press, 1991
Buku Teks