Greenbaum, Sidney
Longman , 1990
Buku Teks
Kaplan, Jeffrey P., author
Prentice Hall International, 1995
Buku Teks
Thomson, A.J., author
Oxford Oxford University Press, 1986
Buku Teks
Woods, Geraldine, author
John Wiley & Sons, 2015
Buku Teks
Anderson, W.M. (Wendy M.), author
Wiley Publishing , 2013
Buku Teks