  Using the 1/N_C expansion scheme and truncating the hadronic spectrum to the
lowest-lying multiplets of resonances we develop a procedure to implement QCD
information on the non-perturbative regime populated by resonances through the
use of three-point Green Functions of QCD currents. The process implies to
enforce on these functions the constraints provided by their asymptotic
behaviour ruled by QCD using their OPE or associated form factors. As a result
we are able to determine several couplings of the O(p^6) Chiral Perturbation
Theory Lagrangian and, in consequence, to address phenomenological issues such
as the SU(3) breaking in Kl3 decays.
