1. “Weak Second Order Arithmetic and Finite Automata”;Büchi;Zeitschrift für Math. Log. und Grundl. der Math.,1960
2. Church, Alonzo. “Application of Recursive Arithmetic to the Problem of Circuit Synthesis”, Notes of the Summer Institute of Symbolic Logic, Cornell, 1957, pp. 3–50, and “Application of Recursive Arithmetic in the Theory of Computing and Automata”, Notes: Advanced Theory of the Logical Design of Digital Computers, U. of Michigan Summer Session, 1959.
3. “Realization of Events by Logical Nets”;Copi;Journal of the Association for Computing Machinery,1958
4. “Some Results in Church's Restricted Recursive Arithmetic”;Friedman;Journal of Symbolic Logic,1957
5. “Representation of Events in Nerve Nets and Finite Automata”;Kleene,1956