1. Delayed-logic and finite-state machines;Arden,1961
2. Mathematical Theory of Automata;Buchi,1960
3. The Algebraic Theory of Context-Free Languages;Chomsky,1963
4. On relations defined by generalized finite automata;Elgot;IBM J. Res. Develop.,1965
5. Two families of languages related to ALGOL;Ginsburg;J. Assoc. Comp. Mach.,1962