Comment on "Band-Structure Trend in Hole-Doped Cuprates and Correlation   with T_c_max"
  The purpose of the present Comment is to emphasize that the missing link has already been found, and the correlation reported by Pavarini et al., Phys. Rev. Lett. 87, 047003 (2001) [http://dx.doi.org/10.1103/PhysRevLett.87.047003] can be used as a crucial test for theoretical models of HTSC. Perhaps the simplest possible interpretation, though one could search for alternatives, is given within the framework of the Cu 4s-Cu 3d two-electron exchange theory of HTSC, J. Phys.: Condens. Matter 15, 4429 (2003) [http://dx.doi.org/10.1088/0953-8984/15/25/312]. 
T. M. Mishonov