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\newblock {\em Lin. Algebra Appl. 59}, pages 3--15, 1984.

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\newblock Block preconditioning for the conjugate gradient method.
\newblock {\em SIAM J. Sci. Stat. Comp. 6}, pages 220--252, 1985.

\bibitem{Hem83KWdZ}
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\newblock {\em Appl. Math. Comp.}, 13:311--326, 1983.

\bibitem{Kett_87}
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\newblock {\em Linear Multigrid Methods for Numerical Reservoir Simulation}.
\newblock University of Technology, Delft, december 1987.
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\bibitem{Meu84}
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\newblock The block preconditioned conjugate gradient method on vector
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\newblock {\em BIT}, 24:623--633, 1984.

\bibitem{Saa86S}
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\newblock {GMRES}: a generalized minimal residual algorithm for solving
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\newblock {\em SIAM J. Sci. Stat. Comp.}, 7:856--869, 1986.

\bibitem{vdV92}
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\newblock {\em SIAM J. Sci. Stat. Comp.}, 13:631--644, 1992.

\end{thebibliography}
