On the equivalence of an exhaustion principle and the axiom of choice T. Neubrunn — 1967 Fundamenta Mathematicae
Separate continuity and continuity for some generalized continuity notions Neubrunn, T. — 1977 General topology and its relations to modern analysis and algebra IV
An elementary approach to some applications of nonstandard analysis Neubrunn, T.; Riečan, B.; Riečanová, Z. — 1984 Proceedings of the 11th Winter School on Abstract Analysis