“…It has been successfully applied to solve some partial differential equations with the integer order (see [23][24][25][26][27][28][29][30][31] for more details). Recently, Mustapha [32], Zheng and Zhao [33], Liu et al [34], Liu et al [35], Bu et al [36], Yue et al [37], and Li et al [38] developed a finite element scheme for the fractional diffusion equation, fractional diffusion wave equation, linear space fractional PDE, nonlinear fractional reaction diffusion system, multi-term time-space fractional diffusion equation, multi-term time fractional advection-diffusion equations, and fractional wave problems, for which the space-time finite element method was adopted.…”