[ACM] CACM 1(06) (June 1958)

(1957) Communications of the ACM  

[Bemer] (1958) [Bemer, RW] [Addendum to the Automatic Programming Systems Chart of 1(4)] June 1958 Voorhees, Edward A. (1958) Voorhees, Edward A. "Algebraic formulation of flow diagrams" pp4-8