@article{M2AN_1998__32_4_479_0,
     author = {Chen, Zhangxin},
     title = {Expanded mixed finite element methods for linear second-order elliptic problems, {I}},
     journal = {ESAIM: Mathematical Modelling and Numerical Analysis },
     pages = {479--499},
     publisher = {Elsevier},
     volume = {32},
     number = {4},
     year = {1998},
     mrnumber = {1636376},
     zbl = {0910.65079},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/M2AN_1998__32_4_479_0/}
}