Mitropolskiy, Yu. A., and V. V. Strok. “50 Years of ‘Ukrainskii Matematicheskii Zhurnal’”. Ukrains’kyi Matematychnyi Zhurnal, vol. 51, no. 5, May 1999, pp. 579–580, https://umj.imath.kiev.ua/index.php/umj/article/view/4644.