  We extend existing dispersive approach in subloop insertion to the case of
crossed two-loop box type topologies. Based on the ideas of the Feynman trick,
mass shift approach and dispersive representation of two-point
Passarino-Veltman function we expressed two-loop scalar diagrams in the compact
analytical form suitable for the automatization of the calculations. The
results are expressed in a way that the numerical integration over Feynman and
dispersive parameters and differentiation with respect to mass shift parameters
are required in the final stage only.
