V. I. Kolyada, “On Cèsaro and Copson norms of nonnegative sequences”, Ukr. Mat. Zhurn., vol. 71, no. 2, pp. 220–229, Feb. 2019, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1433