1. Altschule, M. D., and Blumgart, H. L. (1937). Amer. Heart J., 13, 589.
2. Bland, E. F., Jones, T. D., and White, P. D. (1935). Ibid., 10, 3.
3. Facts on the Heart;Cabot, Richard,1926
4. Castex, M. R., Battro, A., and Quirno, W. (1937). Rev. Argent. Cardiol., 4, 113.
5. Clements, A. B. (1935). Amer. J. med. Sci., 190, 389.