Hongwei Li, Xiaonan Wu and Jiwei Zhang. (2018). Numerical Solution of the Time-Fractional Sub-Diffusion Equation on an Unbounded Domain in Two-Dimensional Space.
            <i>East Asian Journal on Applied Mathematics</i>. <i>7</i> (3).
            439-454.
         doi:10.4208/eajam.031116.080317a