Harvard Business School Press, 1998
Buku Teks
John, E.A., author
Pergamon, 1973
Buku Teks
Ginzberg, Eli, 1911-, author
Columbia Univesity Press, 1957
Buku Teks
Quirke, Bill, author
McGraw-Hill, 1995
Buku Teks
Kissler, Gary D., author
Addison-Wesley, 1991
Buku Referensi