Hague, D. C.
George Allen and Unwin , 1974
Buku Teks
Hammond, John S., 1937-, author
Harvard Business School, 1999
Buku Teks
Cooke, Steve
Prentice-Hall, 1991
Buku Teks
Moody, Paul E.
McGraw-Hill, 1983
Buku Teks
Clough, Donald J.
Prentice-Hall, 1983
Buku Teks