STEPANETS, O. I. Several statements for convex functions. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 51, n. 5, p. 688–702, 1999. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4654. Acesso em: 14 apr. 2025.