Cunyun Nie, Shi Shu, Haiyuan Yu and Juan Wu. (2013). Superconvergence and Asymptotic Expansions for Bilinear Finite Volume Element Approximations.
            <i>Numerical Mathematics: Theory, Methods and Applications</i>. <i>6</i> (2).
            408-423.
         doi:10.4208/nmtma.2013.1127nm