VELYKOCHYY, V. et al. 2019. TO THE 80TH ANNIVERSARY OF PROFESSOR KALAKURA YA.S. AND THE 55TH ANNIVERSARY OF HIS SCIENTIFIC AND PEDAGOGICAL ACTIVITY. Journal of Vasyl Stefanyk Precarpathian National University. 6, 2 (Jun. 2019), 133–137. DOI:https://doi.org/10.15330/jpnu.6.2.133-137.