Ashley, Maurice, author
Frederick A. Praeger, 1969
Buku Teks
Namho, Lee, author
EastBridge, 2005
Buku Teks
Gray, Richard, 1944-, author
Longman, 1991
Buku Teks
edited by Brian Docherty
Macmillan, 1994
Buku Teks
Berkowitz, Gerald M., author
Longman, 1994
Buku Teks