Calverley, John
American Express Bank , 1994
Buku Teks
Auel, Jean M.
Bantam Books, 1980
Buku Teks
Hovey, Craig, author
Prenada, 2009
Buku Teks
Nahmias, Steven
McGraw-Hill , 2001
Multimedia
Thomsett, Michael C., author
American Management Association, 2007
eBooks