EDITORIALBOARD. Index of volume 69 of „Ukrainian Mathematical Journal”. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 69, n. 12, p. 1723–1729, 2017. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1816. Acesso em: 5 dec. 2025.