On l-groups of uniformly continuous functions. III. Proximity spaces. Jens Erik Fenstad — 1964 Mathematische Zeitschrift
On ...-groups of uniformly continuous functions. I. Approximation theory. Jens Erik Fenstad — 1963 Mathematische Zeitschrift
On l-groups of uniformly continuous functions. II. Representation theory. Jens Erik Fenstad — 1964 Mathematische Zeitschrift
On the Consistency of the Axiom of Comprehension in the Lukasiewicz Infinite Valued Logic. Jens Erik Fenstad — 1964 Mathematica Scandinavica