1. Consistency proof for the General Continuum Hypothesis;Gödel,1935
2. Metarecursive sets;Kreisel;J. Symbolic Logic,1966
3. Transfinite recursions on admissible ordinals, I, II (abstracts);Kripke;J. Symbolic Logic,1964
4. Admissible ordinals and the analytic hierarchy (abstract);Kripke;J. Symbolic Logic,1964
5. Post's problem, admissible ordinals, and regularity;Sacks;Trans. Amer. Math. Soc.,1966