1. Alikhanov, A.A.: Boundary value problems for the diffusion equation of the variable order in differential and difference settings. Appl. Math. Comput. 219 (8), 3938–3946 (2012)
2. An, Y., Liu, R.: Existence of nontrivial solutions of an asymptotically linear fourth-order elliptic equation. Nonlinear Anal. 68(11), 3325–3331 (2008)
3. Chen, H., Stynes, M.: Blow-up of error estimates in time-fractional initial-boundary value problems. IMA J. Numer Anal. (To appear) (2020)
4. Diethelm, K.: The Analysis of Fractional Differential Equations volume 2004 of Lecture Notes in Mathematics. Springer, Berlin (2010). An application-oriented exposition using differential operators of Caputo type
5. Evans, L.C.: Partial Differential Equations, volume 19 of Graduate Studies in Mathematics. American Mathematical Society, Providence (1998)