Numerical Computation of Two-loop Box Diagrams with Masses
  A new approach is presented to evaluate multi-loop integrals, which appear in the calculation of cross-sections in high-energy physics. It relies on a fully numerical method and is applicable to a wide class of integrals with various mass configurations. As an example, the computation of two-loop planar and non-planar box diagrams is shown. The results are confirmed by comparisons with other techniques, including the reduction method, and by a consistency check using the dispersion relation. 
F. Yuasa, E. de Doncker, N. Hamaguchi, T. Ishikawa, K. Kato, Y.   Kurihara, J. Fujimoto, Y. Shimizu
hep-ph