Roberts C S, Gertz S D, Klues H G, Cannon R O, Maron B J, McIntosh C L, Roberts W C
Surgery, Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
Am J Cardiol. 1991 Dec 15;68(17):1726-8. doi: 10.1016/0002-9149(91)90341-h.