Parrot, Martin, author
Cambridge University Press, 2003
Buku Teks
Greenbaum, Sidney
Longman , 1990
Buku Teks
Makkink, H.J., author
Nijgh and Van Ditmar, 1951
Buku Teks
Kaplan, Jeffrey P., author
Prentice Hall International, 1995
Buku Teks
Newby, Michael, author
Cambridge University Press, 1988
Buku Teks