@article{NUMA_1990__58_5_133496,
     author = {W. D\"orfler},
     title = {The conditioning of the stiffness matrix for certain elements approximating the incompressibility condition in fluid dynamics.},
     journal = {Numerische Mathematik},
     pages = {203--214},
     publisher = {mathdoc},
     volume = {58},
     number = {5},
     year = {1990},
     zbl = {0705.76026},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1990__58_5_133496/}
}