GubreevG. M., OlefirE. I., & TarasenkoA. A. (2013). Linear Combinations of the Volterra Dissipative Operator and Its Adjoint Operator. Ukrains’kyi Matematychnyi Zhurnal, 65(5), 706–711. Retrieved from http://umj.imath.kiev.ua/index.php/umj/article/view/2453