Rapport entre l'ensemble des ultrafiltres admettant un ultrafiltre donné pour image et l'ensemble des images de cet ultrafiltre Maryvonne Daguenet (1975) Commentationes Mathematicae Universitatis Carolinae
Representations of presheaves of semiuniformisable spaces, and representation of a presheaf by the presheaf of all continuous sections in its covering-space Jaroslav Drahoš (1971) Czechoslovak Mathematical Journal