Yotsukura, Sayo
Mouton , 1970
Buku Teks
Stone, Linton
Macmillan, 1970
Buku Teks
Swan, Michael, author
Cambridge University Press, 1987
Buku Teks
Sharpe, Pamela J., author
Barron's, 2001
Buku Teks
French, F. G., author
Oxford University Press, 1951
Buku Teks