@article{GDZPPN001170848, title = {On Minimal Gerschgorin Sets for Families of Norms.}, journal = {Numerische Mathematik}, volume = {19}, year = {1972}, pages = {252-256}, zbl = {0302.65029}, url = {http://dml.mathdoc.fr/item/GDZPPN001170848} }
Varga, Richard S.; Levinger, Bernard W. On Minimal Gerschgorin Sets for Families of Norms.. Numerische Mathematik, Tome 19 (1972) pp. 252-256. http://gdmltest.u-ga.fr/item/GDZPPN001170848/