Mackenizie, John
Illinois: Dow Jones-Irwin, 1989
Buku Teks
Scharf, Charles A.
Prentice-Hall, 1985
Buku Teks
Brause, Rita S.
RoutledgeFalmer , 2000
Buku Teks
edited by Stockton B. Colt
[American Management Association, ], 1998
eBooks
Thomas, Wayne M.
Amacom, 2008
Buku Teks