  A sum rule analysis of the hadronic tau-decay data can be used to determine
the low-energy constants L10(mu) and C87(mu). These constants are QCD
chiral-order parameters, which appear at order p^4 and p^6, respectively, in
the chiral perturbation theory expansion of the V-A correlator. At order p^4 we
obtain L10(M_rho) = -(5.22\pm 0.06)10^-3. Including in the analysis the order
p^6 contributions, we get L10(M_rho) = -(4.06\pm 0.39)10^-3 and C87(M_rho) =
(4.89\pm 0.19)10^-3 GeV^-2.
