1. Sharpening the characterization of the power of Floyd's method;Andréka,1983
2. Completeness of Floyd logic;Andréka;Bull. Section of Logic (Wroclaw),1978
3. Completeness problems in verification of programs and program schemes;Andréka,1979
4. Henkin-type semantics for program schemes to turn negative results to positive;Andréka,1979