SO(N) invariant Wess-Zumino action and its quantization
  A consistent quantization procedure of anomalous chiral models is discussed. It is based on the modification of the classical action by adding Wess-Zumino terms. The $SO(3)$ invariant WZ action for the $SO(3)$ model is constructed. Quantization of the corresponding modified theory is considered in details. 
S.A.Frolov, A.A.Slavnov and C.Sochichiu