@article{NUMA_1990__58_5_133526,
     author = {G.W. Stewart and G. Zhang},
     title = {Eigenvalues of graded matrices and the condition numbers of a multiple eigenvalue.},
     journal = {Numerische Mathematik},
     pages = {703--712},
     publisher = {mathdoc},
     volume = {58},
     number = {5},
     year = {1990},
     zbl = {0697.65027},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1990__58_5_133526/}
}