BerezanskyYu. M., GorbachukV. I., GorbachukM. L., KorolyukV. S., MitropolskiyYu. A., SamoilenkoA. M., and TarasovV. G. 1995. “On the 60th Birthday of Leonid Pavlovich Nizhnik”. Ukrains’kyi Matematychnyi Zhurnal 47 (10), 1416–1417. https://umj.imath.kiev.ua/index.php/umj/article/view/5536.