Tarasenko, A. A., and G. D. Urum. “On a Class of Generators of One-Parameter $C_{0}$-Semigroup of Operators”. Methods of Functional Analysis and Topology 9, no. 2 (June 25, 2003): 179–184. Accessed February 4, 2026. https://zen.imath.kiev.ua/index.php/mfat/article/view/213.