1. Evans, W. (1951). Brit. Heart J., 13, 457.
2. Unipolar Lead Electrocardiography and Vectorcardiography;Goldberger, E.,1953
3. Herrmann, G. R., and Wilson, F. N. (1922). Heart, 9, 91.
4. Clinical Electrocardiography;Holzmann, M.,1952
5. Electrocardiography;Katz, L.N.,1946