Color decomposition of multi-quark one-loop QCD amplitudes
  In this talk we discuss the color decomposition of tree-level and one-loop QCD amplitudes with arbitrary numbers of quarks and gluons. We present a method for the decomposition of partial amplitudes into primitive amplitudes, which is based on shuffle relations and is purely combinatorial. Closed formulae are derived, which do not require the inversion of a system of linear equations. 
Christian Reuschle, Stefan Weinzierl
hep-ph hep-th