1. BEAUQUIER D., 1984, Bilimites de langages reconnaissables, a paraitre dans Theoret. Comput. Sci.
2. BUCHI, J.R., 1962, On a decision method in restricted second order arithmetic, in Logic, Methodology and Philosophy of Science, (Proc. 1960 Internat. Cong.), Stanford University Press, Stanford.
3. EHRENFEUCHT A., LEE R.P., ROZENBERG G., 1975, Subwords complexities of various classes of deterministic developmental languages without interactions, Theoretical Computer Science 1 p. 59–76.
4. EILENBERG, S., 1974, Automata, Languages and Machines, Vol. A, Academic Press, New York, Vol. B, 1976.
5. FISCHER R., 1975, Sofic systems and graphs Monats. Math. 80 179–186.