Goginava, U. “Strong Summability of Two-Dimensional Vilenkin – Fourier Series”. Ukrains’kyi Matematychnyi Zhurnal 71, no. 3 (March 25, 2019): 340–352. Accessed April 11, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/1443.