Reutov, O., author
Mir, 1976
Buku Teks
Griffin, Rodger W., author
McGraw-Hill, 1969
Buku Teks
Watson, H.B., author
Oxford University Press , 1949
Buku Teks
Norman, R.O.C., author
The English Language Book Society, 1978
Buku Teks
Ouellette, Robert J., author
Prentice-Hall, 1994
Buku Teks