V. M. Statkevych, “Investigation of solutions of boundary-value problems with essentially infinite-dimensional elliptic operator”, Ukr. Mat. Zhurn., vol. 64, no. 2, pp. 229–236, Feb. 2012, Accessed: Apr. 07, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2569