[1]
V. A. Andrienko, “On the order of growth of rectangular partial sums of double orthogonal series”, Ukr. Mat. Zhurn., vol. 51, no. 10, pp. 1299–1310, Oct. 1999, Accessed: Apr. 13, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/4728