The rational parts of one-loop QCD amplitudes II: The five-gluon case
  The rational parts of 5-gluon one-loop amplitudes are computed by using the newly developed method for computing the rational parts directly from Feynman integrals. We found complete agreement with the previously well-known results of Bern, Dixon and Kosower obtained by using the string theory method. Intermediate results for some combinations of Feynman diagrams are presented in order to show the efficiency of the method and the local cancellation between different contributions. 
Xun Su, Zhi-Guang Xiao, Gang Yang, Chuan-Jie Zhu