“…a large number of papers on this subject are available in the literature, where various decay estimates for the solutions of (4) were obtained; see in this regard [6,8,9,22,27,28,29,30] and the references cited therein. For the particular case of the wave equation with (internal or boundary) finite memory; see [2,1,7,43] and [44]- [52]. See also [21] for the wave equation with complementary finite and infinite memories, and [20] for the Timoshenko systems with complementary finite memory and nonlinear frictional damping.…”