@article{NUMA_1973__21_132211,
     author = {H.J. de Vries},
     title = {On the {Eigenproblem} for {Normal} {Matrices.}},
     journal = {Numerische Mathematik},
     pages = {37--42},
     publisher = {mathdoc},
     volume = {21},
     year = {1973},
     zbl = {0247.65023},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1973__21_132211/}
}