Results from the paper

  S. Bekavac, A. Grozin, D. Seidel, M. Steinhauser:
  Light quark mass effects in the on-shell renormalization constants,
  TTP07-21 

(see also: 
http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/webmaster/abs2html?ttp07-21)

See readme.ps for details.