AndrienkoV. A. (1999) “On the order of growth of rectangular partial sums of double orthogonal series”, Ukrains’kyi Matematychnyi Zhurnal, 51(10), pp. 1299–1310. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4728 (Accessed: 24November2024).