Lehman, Carol M., author
Thomson South-Western, 2006
Buku Teks
Coulthard, Glen J., author
McGraw-Hill, 2003
Buku Teks
Mills, Harry, author
American Management Association, 2007
eBooks
Lindstrom, Robert L.
McGraw-Hill , 1994
Buku Teks
Microsoft Press, 1995
Buku Teks