1. S. G. Krein, Linear Differential Equations in a Banach Space [in Russian], Nauka, Moscow (1967).
2. A. Pazy, Semigroups of Linear Operators and Applications to Partial Differential Equations, Springer, New York (1983).
3. E. Hille and P. Phillips, Functional Analysis and Semigroups [Russian translation], IL, Moscow (1962).
4. N. Dunford, J. Schwartz, Linear Operators, Vol. I [Russian translation], IL, Moscow (1962).
5. A. V. Balakrishnan, Applied Functional Analysis [Russian translation], Nauka, Moscow (1980).