French, F. G.
Oxford University Press, 1947
Buku Teks
Pincas, Anita
Macmillan Press, 1983
Buku Teks
Puchta, Herbert
Cambridge University Press, 2010
Buku Teks
Howard, Godfrey
Pan Macmillan Publishers, 1993
Buku Referensi
Drummond, Gordon
Essex Longman, 1972
Buku Teks