• Altman DG (1994). Practical Statistics for Medical Research. London: Chapman and Hall.
  • Apgar V (1953). Proposal for a new method of evaluation of newborn infants. Anesthesia and Analgesia 32: 2607.
  • Bland JM (2000). An Introduction to Medical Statistics (3rd edn.) Oxford: Oxford University Press.
  • Croft P, Pope D, Zonca M, O'Neill T, Silman A (1994). Measurement of shoulder related disability: Results of a validation study. Annals of the Rheumatic Diseases 53: 5258.
  • EuroQol Group (1990). Euro-Qol –a new facility for the measurement of health-related quality of life. Health Policy 16: 199208.
  • Jordan K, Ong BN, Croft P (1998). Mastering Statistics: A Guide for Health Service Professionals and Researchers. Cheltenham: Stanley Thornes (Publishers) Ltd.
  • Meenan RF, Mason JH, Anderson JJ, Guccione AA, Kazis LE (1992). AIMS2: The content and properties of a revised and expanded Arthritis Impact Measurement Scales health questionnaire. Arthritis and Rheumatism 35: 110.
  • Swinscow TDV (1998). Statistics at Square One (9th edn.) London: BMJ Publishing Group.
  • World Health Organization (2000). Obesity: Preventing and Managing the Global Epidemic. WHO Technical Report Series 894. Geneva: WHO.
  • Zigmond AS, Snaith RP (1983). The Hospital Anxiety and Depression Scale. Acta Psychiatrica Scandinavica 67: 36170.