1. Thomas, L., ‘The health care system’, N Engl J Med, 293:1245, 1975
2. McKeown, T., ‘An approach to screening policies’, J Roy Coll Phys, 10:145, 1976
3. Wilson, J., ‘Some principles of early diagnosis in general practice’ in Surveillance and Early Diagnosis in General Practice, G. Teeling-Smith (ed), Office of Health Economics, London, 1966
4. WHO Public Health Paper No. 45;World Health Organization,1971
5. Spitzer, W. & Brown, B., ‘Unanswered questions about the periodic health examination’, Ann Int Med, 83:257, 1975