veronika.korenkova@umb.sk
jan.zavadsky@umb.sk
mlis@wsb.edu.pl
© 2019 Veronika Korenková, Ján Závadský, Marcin Lis, published by Bialystok University of TechnologyThis work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.