Beatty, Richard H.
John Wiley & Sons, 1986
Buku Teks
Falcone, Paul, author
American Management Association, 2009
eBooks
Fry, Ron, author
Career Press, 2002
Buku Teks
Martin, Carole, author
McGraw-Hill, 2012
Buku Teks
Beveridge, Wilbert Esler, author
Allen & Unwin, 1975
Buku Teks