KOFANOV, V. A. On some extremal problems of different metrics for differentiable functions on the axis. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 61, n. 6, p. 765–776, 2009. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3057. Acesso em: 6 dec. 2025.