@article{NUMA_1986__49_133106,
     author = {J., Jr. Douglas and Chaitan P. Gupta},
     title = {Superconvergence for a {Mixed} {Finite} {Element} {Method} for {Elastic} {Wave} {Propagation} in a {Plane} {Domain.}},
     journal = {Numerische Mathematik},
     pages = {189--202},
     publisher = {mathdoc},
     volume = {49},
     year = {1986},
     zbl = {0607.73027},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1986__49_133106/}
}