M. N. Feller, Y. I. Belopolskaya, and S. Albeverio, “Boundary problems for the wave equation with the Lévy Laplacian in Shilov’s class”, MFAT, vol. 16, no. 3, pp. 197–202, Sep. 2010, Accessed: Feb. 04, 2026. [Online]. Available: https://zen.imath.kiev.ua/index.php/mfat/article/view/451