1. Generalized Automata Theory with an Application to a Decision Problem of Second-Order Logic;Thatcher;IBM Research RC 1713,1966
2. A Further Generalization of Finite Automata;Thatcher;IBM Research RC 1846,1967
3. Generalized ALGOL-like languages;Mezei;IBM Research Paper RC 1528,1965
4. Characterizing Derivation Trees of Context-Free Grammars through Generalized Finite Automata Theory;Thatcher;IBM Research Note NC 719,1967
5. Mathematical Automata Theory;B\:uchi,1960