Zagorodnii , A. G., A. M. Samoilenko, V. A. Bugrov, V. P. Mel’nyk, M. Z. Zgurovs’kyi, M. V. Stricha, and N.O. Virchenko. 2022. “On the 100th Birthday of Outstanding Scientist Ostap Stepanovych Parasyuk (20.12.1921 – 22.11.2007)”. Ukrains’kyi Matematychnyi Zhurnal 74 (2), 286 -88. https://doi.org/10.37863/umzh.v74i2.6873.