“…Even in the kingdom of diffusion, the central pillars of anomalous diffusion, including sub-diffusion and super-diffusion, long-range dependence (LRD), 1/f noise, and Lévy statistics, have intrinsic power-law structures [12]; and the corresponding fractional diffusion equations have been much better investigated than the power law wave equation [5,10,16,17,32,37]. For the diffusion-wave equations, there are also some discussions, including analysis, algorithm, and applications; the fundamental solutions and their properties are considered in [1,24,25,30]; and different kinds of numerical methods and approximation schemes have also been developed, e.g., the finite difference method [33,38], spectral method [4], and finite element method [13,18], etc.…”