The Undecidability of Gris˘in's Set Theory
Categorical Abstract Algebraic Logic Metalogical Properties*
Second-order Non-nonstandard Analysis
Closure Operators and Complete Embeddings of Residuated Lattices
On Alternative Geometries, Arithmetics, and Logics; a Tribute to Łukasiewicz
Dirk Van Dalen, Mystic, Geometer, and Intuitionist. The life of L.E.J. Brouwer, Volume 1