Beshara, Tony
Amacom, 2011
Buku Teks SO
Eyre, Vivian
Learning Express, 2000
Buku Teks SO
Falcone, Paul
American Management Association, 2009
eBooks
Kay, Andrea
American Management Association, 2013
eBooks
Nierenberg, Alan H.
American Management Association, 2005
eBooks