R. Ali .Zboon, J. Ramadhan.Kider, and S. Kasim .Hassan, “Solvability and Admissibility of Linear Perturbed Unbounded Differential Operator Equations with Unbounded Control input Via Composite perturbation Semigroup Approach”, J. Al-Qadisiyah Comp. Sci. Math., vol. 3, no. 1, pp. 101–129, Sep. 2017.