DOROGOVTSEV, A. A.; KOPYTKO, B.I.; KOROLYUK, V. S.; MITROPOLSKIY, Yu. A.; SAMOILENKO, A. M.; SYTAYA, G. N.; SKOROKHOD, A. V. Mykola Ivanovych Portenko (On His 60th Birthday). Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 2, p. 147–148, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4050. Acesso em: 5 dec. 2025.