EDITORIAL BOARD. Mstislav Vsevolodovich Keldysh (On his 60th birthday) . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 23, n. 2, p. 218–220, 1971. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8503. Acesso em: 6 dec. 2025.