1. Blondeau, M., P. Rizzon and J. Lenegre, Arch. Mal. Coeur 10, 1092 and 1194 (1961).
2. Clarke, J.A., Brit. Heart J. 27, 879 (1965).
3. Cohen, D.B., L. Doctor and A. Pick, Amer. Heart J. 55, 215 (1958).
4. Courter, S.R., J. Moffat, N.O. Fowler, Circulation 27, 1034 (1963).
5. Davies, M.J., Pathology of conducting tissue of the heart, Butterworths, London (1971).