MikhailetsV. A., and MurachA. A. “Extended Sobolev Scale and Elliptic Operators”. Ukrains’kyi Matematychnyi Zhurnal 65, no. 3 (March 25, 2013): 392-404. Accessed November 23, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2426.