Hammond, John S., 1937-
Harvard Business School, 1999
Buku Teks
Eden, Colin
Macmillan, 1975
Buku Teks
Ibnu Syamsi
Bina Aksara, 1989
Buku Teks
Radford, K.J.
Prushin-Hall, 1974
Buku Teks
edited by Anthony G. McGrew
Manchester University Press, 1985
Buku Teks