French, F. G., author
Oxford University Press, 1947
Buku Teks
Barker, D. W.
Macmillan and Co., 1953
Buku Teks
Drummond, Gordon, author
Essex Longman, 1972
Buku Teks
Hewings, Martin, author
Cambridge University Press , 2004
Buku Teks
Dowling, Barbara Tolley
Newbury House Publishers , 1982
Buku Teks