PEROV, A. I. On guestions of the general theory of convex functions . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 18, n. 3, p. 129–132, 1966. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8748. Acesso em: 7 apr. 2025.