Drummond, Gordon, author
Essex Longman, 1972
Buku Teks
V.S. Belevitskaya-Khalizeva ...[et al.]
Foreign Languages Publishing House, [date of publication not identified]
Buku Referensi
French, F. G., author
Oxford University Press, 1947
Buku Teks
Tregidgo, Philip Sillince
Longman, 1979
Buku Teks
Willis, Dave, author
Cambridge University Press, 2003
Buku Teks