GorbachukM. L., ZadereiP. V., LukovskyI. O., MakarovV. L., MotornyiV. P., RomanyukA. S., SamoilenkoA. M., SerdyukA. S., and SharkoV. V. “Oleksandr Ivanovych Stepanets’ (on the 70 Th Anniversary of His Birthday)”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 64, no. 5, May 2012, pp. 579-81, https://umj.imath.kiev.ua/index.php/umj/article/view/2598.