O. I. Terek https://orcid.org/0000-0003-0230-4166 Ivan Franko National University of Lviv Ukraine
S. O. Hnatush https://orcid.org/0000-0002-5353-102X Ivan Franko National University of Lviv Ukraine
Z. I. Mamchur https://orcid.org/0000-0003-0527-5639 Ivan Franko National University of Lviv Ukraine