V. M. Merlavsky Ivan Franko National University of Lviv Ukraine
B. O. Manko https://orcid.org/0000-0002-6905-8580 Ivan Franko National University of Lviv Ukraine
O. V. Ikkert https://orcid.org/0000-0002-4893-7340 Ivan Franko National University of Lviv Ukraine
V. V. Manko https://orcid.org/0000-0002-4406-1732 Ivan Franko National University of Lviv Ukraine