1.Wirth,Niklaus,and Hoare C.A.R.A contribution to the development of ALGOL.Comm. ACM9(Uune1966,413-432. 2.BOhm,Corrado,and Jacopini Guiseppe.Flow diagrams,Turing machines and languages with only two formation rules.Comm.ACM 9(May 1966),366-371. Edsger W.Dijkstra Technological University Eindhoven,The Netherlands1. Wirth, Niklaus, and Hoare C. A. R. A contribution to the development of ALGOL. Comm. ACM 9 (June 1966), 413-432. 2. BÖ hm, Corrado, and Jacopini Guiseppe. Flow diagrams, Turing machines and languages with only two formation rules. Comm. ACM 9 (May 1966), 366-371. Edsger W. Dijkstra Technological University Eindhoven, The Netherlands