Shuangzhang Tu, Gordon W. Skelton and Qing Pang. (2012). Extension of the High-Order Space-Time Discontinuous Galerkin Cell Vertex Scheme to Solve Time Dependent Diffusion Equations.
            <i>Communications in Computational Physics</i>. <i>11</i> (5).
            1503-1524.
         doi:10.4208/cicp.050810.090611a