Parrot, Martin, author
Cambridge University Press, 2003
Buku Teks
Berg, Rene van den, author
Foris Publications, 1989
Buku Teks
Thatcher, G.W., author
Frederick Ungar, [Date of publication not identified]
Buku Teks
Greenbaum, Sidney
Longman , 1990
Buku Teks
Lyons, John, author
Cambridge University Press, 1991
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