Downes, Colm
Cambridge English for job-hunting
Cambridge University Press, 2008
 Multimedia
Downes, Colm
Cambridge English for job-hunting
Cambridge University Press, 2008
 Multimedia
Crystal, David, 1941-
The Cambridge encyclopedia of the English language
Cambridge University Press, 1995
 Buku Referensi
Cambridge international dictionary of english
editor in chief Paul Procter
Cambridge University Press, 1995
 Buku Referensi
Lutz, William D.
The cambridge thesaurus of American English
Cambridge University Press, 1994
 Buku Referensi