Golub, G. H. and Van Loan, C. F. (1996), Matrix Computations, 3 Edition, Baltimore: Johns Hopkins University Press.

Greenbaum, A. (1997), Iterative Methods for Solving Linear Systems, Philadelphia: Society for Industrial and Applied Mathematics.

Hestenes, M. R. and Stiefel, E. (1952), “Methods of Conjugate Gradients for Solving Linear Systems,” Journal of Research of the National Bureau of Standards, 46, 409–436.

Paige, C. C. and Saunders, M. A. (1975), “Solution of Sparse Indefinite Systems of Linear Equations,” SIAM Journal on Numerical Analysis, 12, 617–629.