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2. Wood, P., Diseases of the Heart and Circulation, 2nd ed. Eyre & Spottiswoode, London, 1956
3. Friedberg, C. K., Diseases of the Heart, 2nd ed. W. B. Saunders Comp., Philadelphia, 1956
4. Plotz, M., Coronary Heart Disease, P. B. Hoeber, Inc., New York, 1957
5. Morris, J. N., Lancet, 1951 (1), 69