c----------------------------------------------------------------------
      SUBROUTINE GCOR2(A,A1,B1,B2,B3,B4,rtrs,GG,GGRS)
c slimmed down version of GCOR used in PW91 routines, to interpolate LSD correlation 
c energy, as given by (10) of J. P. Perdew and Y. Wang, Phys. Rev. B {\bf 45}, 13244 (1992).
c
c author: K. Burke, May 11, 1996.
c     in:
c    out:
c  calls:
      IMPLICIT REAL*8 (A-H,O-Z)