1. Acheson, R.M., and Acheson, E.D. (1958) Br. J. Prev. Soc. Med.
12, 147.
2. Akhtar, A.J., Broe, G.A., Crombie, A., McLean, W.M.R., Andrews, G.R., and Caird, F.I. (1973) Age and Ageing
2, 190.
3. Anderson, W.F., and Cowan, N.R. (1959) Clin. Sci.
18, 103.
4. Bedford, P.D., and Caird, F.I. (1956) Q. J. Med.
N.S.25, 407.
5. Bedford, P.D., and Caird, F.I. (1960) Valvular Disease of the Heart in Old Age, J & A Churchill, London.