McLean, Gary N., author
Paradigm Publishing, 1991
Buku Teks
The Society of Business Administration, Kwansei Gakuin University, 2009
Majalah, Jurnal, Buletin
Ebert, Ronald J., author
Prentice-Hall, 2009
Buku Teks
edited by Brian Harvey, Henk van Luijk and Horst Steinmann
Prentice-Hall, 1994
Buku Teks
Bearden, James H., author
Holt, Rinehart and Winston , 1969
Buku Teks