1. Nyboer, J. (1941). Amer. Heart J., 22, 469.
2. Standardisation of Precordial Leads;Parkinson, J.; Bedford, D.E.;Heart,1928
3. Wilson, F. N., Hill, I. G. W., and Johnston, F. D. (1934). Ibid., 9, 596.
4. Wilson, F. N., Hill, I. G. W., and Johnston, F. D. (1935). Ibid., 10, 889, 903, and 1025.
5. Wilson, F. N., Hill, I. G. W., and Johnston, F. D. (1938). Ibid., 16, 339.