@article{NUMA_1978__31_132563,
     author = {F. Brezzi and W.W. Hager and P.A. Raviart},
     title = {Error {Estimates} for the {Finite} {Element} {Solution} of {Variational} {Inequalities.} {Part} {II.} {Mixed} {Methods.}},
     journal = {Numerische Mathematik},
     pages = {1--16},
     publisher = {mathdoc},
     volume = {31},
     year = {1978},
     zbl = {0427.65077},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1978__31_132563/}
}