Berezansky, Y. M.; Gorbachuk, V. I.; Gorbachuk, M. L.; Korolyuk, V. S.; Mitropolskiy, Y. A.; Samoilenko, A. M.; Tarasov, V. G. On the 60th Birthday of Leonid Pavlovich Nizhnik. Ukr. Mat. Zhurn. 1995, 47 (10), 1416–1417.