1. Nondeterministic recursive programs;Arnold,1977
2. Fixed point characterization of Büchi automata on infinite trees;Arnold;J. Inform. Process. Cybernet EIK,1990
3. Fixed point characterization of weak monadic logic definable sets of trees;Arnold,1992
4. The modal mu-calculus alternation hierarchy is strict;Bradfield,1996
5. On a decision method in restricted second-order arithmetic;Büchi,1960