On the relations between abstract and geometrical equivalence of abstract objects Mieczysław Kucharzewski; Brunon Szociński; Marek Żabka — 1990 Annales Polonici Mathematici
On difference sets of sets of positive integers Martin Máčaj; Milan Paštéka; Tibor Šalát; Marek Žabka — 2003 Mathematica Slovaca