1.-
Hopcroft, John and Ullman Jefrey.
Introduction to Automata's Theor Languages and Computation.
Ed. Addison-Wesley.
2.- Harry R. Lewis, Chistos H. Papadimitrion. Elements
of the Theory of Computation. Ed. Prentice-Hall.
3.- V. S. Rayward-Smith. A First Course in Formal
Language Theory.
4.- Martin D. Davis and Elaine J. Weyuker. Computability,
Complexity and Languages. Fundamentals of Theoretical
computer Science. Academic Press, Ing. 1983.