1. V. M. Glushkov, Synthesis of Digital Automata [in Russian], Fizmatgiz, Moscow (1962).
2. I. K. Rystsov, ?On weak equivalence of automata,? Kibernetika, No. 4, 30?34 (1990).
3. A. N. Chebotarev, ?Functional design of automata,? in: Intelligent Software for Information/Computing Systems [in Russian], Inst. Kiber. im. V. M. Glushkova AN UkrSSR, Kiev (1990), pp. 12?17.