Vogel, Arthur I.
English Language Book Society, 1958
Buku Teks
Mann, Frederick George
Longman, 1972
Buku Teks
Sharp, J.T.
Chapman and Hall, 1989
Buku Teks
Beyer, Hans
[Publisher not identified], [Date of publication not identified]
Buku Teks
Solomons, T.W. Graham
John Wiley & Sons, 1992
Buku Teks