Y. A. Koval’chuk and Y. V. Kozachenko, “Boundary-Value problems with random initial conditions and functional series from subφ (Ω). I”, Ukr. Mat. Zhurn., vol. 50, no. 4, pp. 504–515, Apr. 1998, Accessed: Apr. 16, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/4920