OSTAPENKO, V. V. Matrix convexity. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 1, p. 64–69, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5383. Acesso em: 5 dec. 2025.