Dorogovtsev, A. A., B.I. Kopytko, V. S. Korolyuk, Yu. A. Mitropolskiy, A. M. Samoilenko, G. N. Sytaya, and A. V. Skorokhod. “Mykola Ivanovych Portenko (On His 60th Birthday)”. Ukrains’kyi Matematychnyi Zhurnal 54, no. 2 (February 25, 2002): 147-148. Accessed May 10, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4050.