1. Hudson, R. E. B. 1970. Cardiovascular Pathology, Vol. 3, S.I28. Arnold, London.
2. Electrocardiographic findings in 67,375 asymptomatic subjects. VII. Atrioventricular block;American Journal of Cardiology
3. Familial heart block and sinus bradycardia. Classification and natural history;Sarachek, N.S.; Leonard, J.L.;American Journal of Cardiology,1972