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<OL>
<LI>C.&nbsp;Slater, <I>Quantum Theory of Molecules and Solids, 
Vol.&nbsp;4</I> (McGraw-Hill, New York, 1974) 
<BR></LI>
<LI>S.J.&nbsp;Vosko, L.&nbsp;Wilk and M.&nbsp;Nusair,
Can.&nbsp;J.&nbsp;Phys.&nbsp;<B>58</B>, 1200 (1980). 
<BR></LI>
<LI>J.&nbsp;P.&nbsp;Perdew and A.&nbsp;Zunger,  Phys.&nbsp;Rev.&nbsp;B <B>23</B>, 5048
(1981). 
<BR></LI>
<LI>J.P.&nbsp;Perdew and Y.&nbs