G. M. Gubreev, E. I. Olefir, and A. A. Tarasenko, “Linear Combinations of the Volterra Dissipative Operator and Its Adjoint Operator”, Ukr. Mat. Zhurn., vol. 65, no. 5, pp. 706–711, May 2013, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2453