Vuković, Mirjana, Emil Ilić-Georgijević, and Olivera Stevanović. “On an Application of Parseval’s Formula to Problems of $G_\theta^\varkappa$-Summability of Eigenfunction Expansion of the Laplacian Operator”. Sarajevo Journal of Mathematics 12, no. 2 (May 30, 2024): 267–276. Accessed January 18, 2025. https://sjm.anubih.ba/index.php/sjm/article/view/194.