M. Bugir, “Theorems on the average values and non-oscillating character of the solutions of the partial differential equations in the spaces $E^n$ and $P^n$ ”, Ukr. Mat. Zhurn., vol. 44, no. 11, pp. 1477–1483, Mar. 2024, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/8248