MOTORNYI, V. P. On the exact constants in Hardy – Littlewood inequalities. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 69, n. 12, p. 1625–1632, 2017. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1809. Acesso em: 5 dec. 2025.