  We derive an estimate for the ratio of the rho mass and the pion decay
constant from an analysis of vector and axial-vector two-point functions using
large-Nc, lowest-meson dominance and the operator product expansion, in the
chiral limit. We discuss the extension of this analysis to the scalar and
pseudoscalar sector. Furthermore, this leads to a successful parameter-free
determination of the L_i couplings of the chiral Lagrangian if an improved
Nambu-Jona-Lasinio ansatz for Green functions is assumed at low energies.
