1. N. D. Kopachevsky and S. G. Krein, Operator Approach to Linear Problems of Hydrodynamics, Vol. 2: Nonself-Adjoint Problems for Viscous Fluids (Birkhäuser, Basel, 2003).
2. G. Amendola, M. Fabrizio, and J. M. Golden, Thermodynamics of Materials with Memory: Theory and Applications (Springer, New York, 2012).
3. A. A. Lokshin and Yu. V. Suvorova, Mathematical Theory of Wave Propagation through Media with Memory (Mosk. Gos. Univ., Moscow, 1982) [in Russian].
4. M. E. Gurtin and A. C. Pipkin, “General theory of heat conduction with finite wave speed,” Arch. Ration Mech. Anal. 31, 113–126 (1968).
5. E. Sanchez-Palencia, Nonhomogeneous Media and Vibration Theory (Springer-Verlag, Berlin, 1980).