Affiliation: | 1.Ivan Franko Lviv National University, 79005, Lviv, Ukraine ;2.Jan Dlugosz University in Czestochowa, 42-200, Czestochowa, Poland ;3.Lviv Polytechnic National University, 79013, Lviv, Ukraine ;4.Ukranian National Forestry University, 79057, Lviv, Ukraine ;5.Karpenko Physico–Mechanical Institute of the National Academy of Sciences of Ukraine, 79060, Lviv, Ukraine ; |