Numerical evaluation of the general massive 2-loop sunrise self-mass   master integrals from differential equations
  The system of 4 differential equations in the external invariant satisfied by the 4 master integrals of the general massive 2-loop sunrise self-mass diagram is solved by the Runge-Kutta method in the complex plane. The method, whose features are discussed in details, offers a reliable and robust approach to the direct and precise numerical evaluation of Feynman graph integrals. 
M. Caffo, H. Czyz and E. Remiddi