Analytical evaluation of certain on-shell two-loop three-point diagrams
  An analytical approach is applied to the calculation of some dimensionally-regulated two-loop vertex diagrams with essential on-shell singularities. Such diagrams are important for the evaluation of QED corrections to the muon decay, QCD corrections to top quark decays t->W^{+}b, t->H^{+}b, etc. 
A.I. Davydychev and V.A. Smirnov