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3. for a review, see The Theory of the Inhomogeneous Electron Gas, S. Lundqvist and N. H. March, eds., Springer Science+Business Media New York (1983); for an extensive discussion of numerical methods.
4. see also, W. E. Pickett, Comp. Phys. Rep.
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5. O. K. Andersen, Phys. Rev.
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