Minimal Gerschgorin sets for partitioned matrices. II: The spectral conjecture. Krautstengl, Alan; Varga, Richard S. — 1995 ETNA. Electronic Transactions on Numerical Analysis [electronic only]

Minimal Gerschgorin sets for partitioned matrices. III: Sharpness of boundaries and monotonicity as a function of the partition. Varga, Richard S.; Krautstengl, Alan — 1995 ETNA. Electronic Transactions on Numerical Analysis [electronic only]