VAKARCHUK, S. B. On some extremal problems of approximation theory in the complex plane. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 56, n. 9, p. 1155–1171, 2004. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3832. Acesso em: 5 dec. 2025.