[1] L. Bieberbach C. Bauer: Vorlesungen über Algebra. Leipzig-Berlin, 1933.

[2] M. Fiedler: On inverting partitioned matrices. Czechoslovak Math. J. (88) 13 (1963), 574-586. MR 0160793 | Zbl 0121.26104

[3] M. Fiedler, Vl. Pták: O jedné iterační metodě diagonalisace symetrických matic. Časopis pěst. mat. 85 (1960), 18-36. MR 0115270

[4] M. Fiedler: Some estimates of proper values of matrices. J. SIAM 13 (1965), No. 2. MR 0179924

[5] A. S. Householder: The Theory of Matrices in Numerical Analysis. Blaisdell Publ. Co., New York-Toronto-London, 1964. MR 0175290 | Zbl 0161.12101

[6] R. S. Varga: On smallest isolated Gerschgorin disks for eigenvalues. Num. Math. 6 (1964), 366-376. DOI 10.1007/BF01386086 | MR 0174172 | Zbl 0131.14204