1. Henrici, P.: Bounds for iterates, inverses, spectral variation and fields of values of non-normal matrices. Num. Math.4, 24–40 (1962).
2. Householder, A. S.: The theory of matrices in numerical analysis. New York:Blaisdell, 1st Ed., 1964.
3. Varah, J. M.: Computing invariant subspaces of a general matrix when the eigen-system is poorly conditioned, to appear.
4. Wilkinson, J. H.: The algebraic eigenvalue problem. Oxford: Clarendon Press, 1st Ed., 1965.