D. A. Nomirovs'kii, “Convergence of the Galerkin method for a wave equation with singular right-hand side”, Ukr. Mat. Zhurn., vol. 58, no. 6, pp. 778–786, Jun. 2006, Accessed: Feb. 16, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3495