1. Buckingham, M. & Clifton, D.O. (2001). Now, discover your strengths; How to develop your talents and those of the people you manage. London: Simon & Schuster.
2. Carkhuff, R.R. (2000). The art of helping in the 21st century (8th ed.). Amherst, MA: Human Resources Development Press.
3. Cohen, J. (1988). Statistical power analysis for behavioral sciences (2nd ed.). Hillsdale, NJ: Lawrence Erlbaum.
4. De Vos, A.S., Strydom, H., Fouché, C.B. & Delport, C.S.L. (2005). Research at grass roots for the social sciences and human services professions (3rd ed.). Pretoria: Van Schaik.
5. Foxcroft, C. & Roodt, G. (2009). Introduction to psychological assessment in the South African context. Cape Town: Oxford University Press.