GorbachukV. M., and GorbachukM. L. “Spaces of Smooth and Generalized Vectors of the generator of an Analytic Semigroup and Their Applications”. Ukrains’kyi Matematychnyi Zhurnal 69, no. 4 (April 25, 2017): 478-509. Accessed December 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/1711.