  We consider the problem of construction of a spectral representation for
nucleon to meson transition distribution amplitudes (TDAs), non-diagonal matrix
elements of nonlocal three quark light-cone operators between a nucleon and a
meson states. We introduce the notion of quadruple distributions and generalize
Radyshkin's factorized Ansatz for this issue. Modelling of baryon to meson TDAs
in the complete domain of their definition opens the way to quantitative
estimates of cross-sections for various hard exclusive reactions.
