Sutton, Garrett, author
Warner Books, 2001
Buku Teks
Coghlan, David, author
Sage, 2001
Buku Teks
Rossoni, Philip, author
McGraw-Hill, 2012
Buku Teks
Rogers, Jenny, author
McGraw-Hill, 2011
Buku Teks
Entrepreneur Press Rich Mintzer
Entepreneur Press, 2011
Buku Teks