Ye , Xiu and Zhang , Shangyou. (2021). Low Regularity Error Analysis for Weak Galerkin Finite Element Methods for Second Order Elliptic Problems.
            <i>Numerical Mathematics: Theory, Methods and Applications</i>. <i>14</i> (3).
            613-623.
         doi:10.4208/nmtma.OA-2020-0120