1. V. M. Glushkov, Synthesis of Digital Automata [in Russian], Fizmatgiz, Moscow (1962).
2. J. Hopcroft, ?An n log n algorithm for minimizing states in a finite automaton,? Theory of Machines and Computation, Proc. Int. Symp., Haifa (1971), pp. 189?196.
3. A. A. Letichevskii and A. B. Godlevskii, ?Optimization of algorithms in the process of their design by the method of formalized technical specifications,? in: Computer-Aided Design of Computers and Computer Components [in Russian], IK Akad. Nauk UkrSSR, Kiev (1977), pp. 46?71.
4. A. B. Godlevskii and S. L. Krivoi, ?Transformation synthesis of efficient algorithms using additional specifications,? Kibernetika, No. 6, 37?43 (1986).
5. P. J. Downey, R. Sethy, and R. E. Tarjan, ?Variations on the common subexpression problem,? J. ACM,17, No. 4, 758?771 (1980).