@article{GDZPPN001165151, title = {On Smallest Isolated Gerschgorin Disks for Eigenvalues.}, journal = {Numerische Mathematik}, volume = {6}, year = {1964}, pages = {366-376}, zbl = {0131.14204}, url = {http://dml.mathdoc.fr/item/GDZPPN001165151} }
VARGA, R.S. On Smallest Isolated Gerschgorin Disks for Eigenvalues.. Numerische Mathematik, Tome 6 (1964) pp. 366-376. http://gdmltest.u-ga.fr/item/GDZPPN001165151/