1. Barber, J. M., Magidson, O., and Wood, P. (1950). Brit. Heart J., 12, 277.
2. Barnes, A. R., and Whitten, M. B. (1929). Ibid., 5, 14.
3. Cohn, A. E., and Raisbeck, M. J. (1921-2). Heart, 9, 311.
4. Einthoven, W. (1906). Arch. Internat. Physiol., 4, 132.
5. Unipolar Lead Electrocardiography;Goldberger, E.,1949