In addition to his work in Hungary, most of his collecting activity took place in the former Yugoslavia, Bulgaria, the Maltese Islands and Italy, where he discovered numerous new mollusk species. On these expeditions, he was a recognized expert on the genera Monacha and Vitrea. A number of new species in those two genera were described by him, and the description of species in other genera was carried out by his colleagues. The results of his scientific research were issued in more than one hundred publications, in Hungary and in other countries.
