Jiming Yang & Zhiguang Xiong. (1970). A Posteriori Error Estimates of a Combined Mixed Finite Element and Discontinuous Galerkin Method for a Kind of Compressible Miscible Displacement Problems.
            <i>Advances in Applied Mathematics and Mechanics</i>. <i>5</i> (2).
            163-179.
         doi:10.4208/aamm.11-m1140