On-shell two-loop three-gluon vertex
  The two-loop three-gluon vertex is calculated in an arbitrary covariant gauge, in the limit when two of the gluons are on the mass shell. The corresponding two-loop results for the ghost-gluon vertex are also obtained. It is shown that the results are consistent with the Ward-Slavnov-Taylor identities. 
A. I. Davydychev (Mainz, Moscow) and P. Osland (Bergen, DESY, CERN)