Dobrovol’skii, V. A., O. B. Lykova, Y. A. Mitropolskiy, M. O. Pustovoytov, A. M. Samoilenko, and V. M. Urbansky. “Olexiy Bogolyubov (03.25.1911 - 01.11.2004)”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 58, no. 4, Apr. 2006, pp. 564–567, https://umj.imath.kiev.ua/index.php/umj/article/view/3474.