GORBACHUK, M. L.; LUCHKA, A. Y.; MITROPOLSKIY, Yu. A.; SAMOILENKO, A. M. Bohdan Iosypovych Ptashnyk. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 9, p. 1155–1156, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5111. Acesso em: 5 dec. 2025.