I. O. Koltun https://orcid.org/0000-0003-2026-0777 Ivan Franko National University of Lviv Ukraine
V. V. Liesnik https://orcid.org/0000-0001-6942-3034 Ivan Franko National University of Lviv Ukraine
I. S. Khamar https://orcid.org/0000-0003-0404-8565 Ivan Franko National University of Lviv Ukraine