1. Barnes, A. R. (1937). J. Amer. med. Ass., 109, 1347. Barnes, C. (1941). Proc.
2. Amer;Eliaser, M.; Giansiracusa, F.,1952
3. Electrocardiographv;Katz, L.N.,1946
4. Kuo, P. T., and Vander Veer, J. B. (1950). Amer. Heart J., 40, 825.
5. Laham, J., and Gerbaux, A. (1951). Arch. Mal. Caeur, 44, 328.