ZABOLOTNYI, Ya. V. On one Dubinin extreme problem. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 64, n. 1, p. 24–31, 2012. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2553. Acesso em: 6 dec. 2025.