1. Baumgarten, W., Ambrus, C. M., McCall, K. B., and Pennell, R. B. (1960). Amer. J. Cardiol., 6, 447.
2. Blix, S. (1961). Scand. J. clin. Lab. Invest., suppl. 58, 11.
3. Douglas, A. S., and McNicol, G. P. (1964). Brit. med. Bull., 20, 228.
4. Fearnley, G. R., Balmforth, G., and Fearnley, E. (1957). Clin. Sci., 16, 645.
5. Kekwick, R. A., and Mackay, M. E. (1954). Spec. Rep. Ser. med. Res. Coaun. (Lond.), No. 286.