1. Tame Σ2 functions in α-recursion theory;Chong,1973
2. Metarecursively enumerable sets and their metadegrees;Driscoll;J. Symb. Logic,1968
3. Two recursively enumerable sets of incomparable degrees of unsolvability;Friedberg,1957
4. The fine structure of the constructible hierarchy;Jensen;Ann. Math. Logic,1972
5. Metarecursive sets;Kreisel;J. Symb. Logic,1965