Chowdhury, Subir
Financial Times Prentice Hall , 2002
Buku Teks
John Wiley , 1981
Buku Teks
Harvard Business School Press, 2003
Buku Teks
Linder, Jane C.
American Management Association, 2008
eBooks
Carr, Albert Z.
New American Library, 1968
Buku Teks