SCHERF, D Return extrasystoles. [electronic resource] - Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.) Feb 1947 - 228-30 p. digital Publication Type: Journal Article ISSN: 0037-9727 Standard No.: 10.3181/00379727-64-15752 doi Subjects--Topical Terms: Arrhythmias, CardiacCardiac Complexes, PrematureHumans