1. Gödel's functional (“Dialectica”) interpretation;Avigad,1998
2. Nets and filters in topology;Bartle;Amer. Math. Monthly,1955
3. Notions of closed subsets of a complete separable metric space in weak subsystems of second-order arithmetic;Brown,1990
4. Notions of compactness in weak subsystems of second order arithmetic;Brown,2005
5. Iterated inductive definitions and subsystems of analysis: recent proof-theoretical studies;Buchholz,1981