1. Lewis, H. R., Papadimitriou, C.
Elements of the theory of computation (Στοιχεία Θεωρίας
Υπολογισμού), translation in greek
Kritiki Publishers, Athens, 2005
2. Hopcroft, J. E., Motwani, R., Ullman, J. D.
Introduction to Automata Theory, Languages, and Computation
Addison Wesley, 2nd Edition, 2003