Ruff diagram could be showing surgical concept, ""Heart Surgery, Bul. N. E. Med. Center 6:49, April '44, Intracardiac Surgery, J. Thor. Surg. 12:566, Aug. '43, Ibid, J. Thor. Surg. II:656, Aug. '42, Heart Surgery, Prec Interst. Post grad. M. A. , North Amer. (1941) pp. 350+ '42
