I. N. Aleksandrovich and M. V. Sidorov, “Differential operators specifying the solution of an elliptictype iterated equation”, Ukr. Mat. Zhurn., vol. 71, no. 3, pp. 433–440, Mar. 2019, Accessed: Feb. 16, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1449