Vitto, John M., author
Corwin Press, 2003
Buku Teks
Pearson Education, Prentice Hall, 2008
Multimedia
Riggs, James L., author
McGraw-Hill, 1974
Buku Teks
Lemlech, Johanna Kasin
Harper & Row , 1979
Buku Teks
Tracy, Brian, author
American Management Association, 2013
eBooks