Results from the paper

  Low energy moments of heavy quark current correlators at four loops
  A. Maier, P. Maierhoefer, P. Marquard, A. Smirnov
  TTP09-18 

(see also: 
http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/webmaster/abs2html?ttp09-18)