CP violating effects in the decay Z -> mu^+mu^-gamma induced by ZZgamma   and Zgammagamma couplings
  We analyze possible CP-violating effects induced in the $Z$ decay with hard photon radiation by $\gamma ZZ$ and $\gamma\gamma Z$ anomalous vertices. We estimate the sensibility of future linear collider experiments on these couplings coming from CP-odd asymmetries associated to angular correlations of the three particle final state in $e^+e^- \to Z \to \mu^+\mu^-\gamma$. We find that a linear collider with an integrated luminosity of 500 $fb^{-1}$ and $\sqrt{s} = 0.05$ TeV can place the bound $|h_1^{\gamma,Z}| < 0.92$ at the 90% confidence level for these couplings. 
M. A. Perez and F. Ramirez-Zavaleta