Authors: W T Butler; R D Rossen; E M Hersh; M E DeBakey; E B Diethrich; D K Brooks; D A Cooley; J J Nora; R D Leachman; D G Rochelle; J J Trentin; K P Judd; A C Beall; D E Jenkins; R O Morgen; V Knight Journal: Nature Date: 1969-11-29 Impact factor: 49.962