Belopolskaya, Ya. I., A. A. Boitsev, S. Fassari, I. Y. Popov, and F. Rinaldi. “Two-Dimensional Helmholtz Resonator With Two Close Point-Like Windows: Regularization for the Neumann Case”. Methods of Functional Analysis and Topology 28, no. 2 (June 25, 2022): 95–104. Accessed December 15, 2025. https://zen.imath.kiev.ua/index.php/mfat/article/view/822.