MokrousovYu. G. “On the Denseness of Subspaces of Analytic Vectors of a Closed Linear Operator in a Banach Space”. Ukrains’kyi Matematychnyi Zhurnal 52, no. 7 (July 25, 2000): 985-989. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4499.