Christo Nel 1954-;Nolan Clarissa Beudeker;2nd ed.. Randburg : Knowres Publishing 2011 Available at Bellville Park Campus Library (BPK 658.4 NEL ) and other locations
Jeff Grimshaw (Jeff D.) (Jeff D.).;Gregg Baron New York : McGraw-Hill Professional c2010 Available at Bellville Park Campus Library (BPK 658.4092 GRI )
Kenneth H Blanchard; Ken Blanchard Companies. Harlow : Financial Times Prentice Hall c2007 Available at JS Gericke Library Lower Level (658.4092 LEA ) and other locations