1. Universality of data retrieval languages;Aho,1979
2. Applications of strict Π11 predicates to infnitary logic;Barwise;J. Symbolic Logic,1969
3. Admissible Sets and Structures;Barwise,1975
4. The next admissible set;Barwise;J. Symbolic Logic,1971
5. Henkin quantifiers and complete problems;Blass;Theoret. Comput. Sc.,1986