The axiom of reflection Antonín Sochor, Petr Vopěnka (1981) Commentationes Mathematicae Universitatis Carolinae
The consistency of the measurability of projective semisets Karel Čuda (1986) Commentationes Mathematicae Universitatis Carolinae
The lattice of indiscernibility equivalences Petr Vopěnka (1979) Commentationes Mathematicae Universitatis Carolinae