M. A. Sukhorolskyi, “Boundary-value problems for the Helmholts equation in domains of the complex plane”, Ukr. Mat. Zhurn., vol. 68, no. 3, pp. 363–376, Mar. 2016, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1844