1. Tabachnick B and Fidell L (1996)Using Multivariate Statistics(3e). Harper Collins: London, p. 640.
2. Pallant J (2001)SPSS Survival Manual. Open University Press: Buckingham.
3. Grant J, Chambers E and Jackson G (1999)The Good CPD Guide: a practical guide to managed CPD. Joint Centre for Education in Medicine: Sutton.
4. Lakhani M, Baker M and Field S (2007)The Future Direction of General Practice. Royal College of General Practitioners: London.
5. Chief Medical Officer (2007)Trust, Assurance and Safety: the regulation of health professionals in the 21st century. Department of Health: London.