The point-splitting regularization of (2+1)d parity breaking models
  The coefficient of the Chern-Simons term in the effective action for massive Dirac fermions in three dimensions is computed by using the point-splitting regularization method. We show that in this framework no ambiguities arise. This is related to the fact that the point-splitting regularization does not introduce additional parity breaking effects, implementing one possible physical criterion in order to uniquely characterize the system. 
D.G. Barci, J.F. Medeiros Neto, L.E. Oxman and S.P. Sorella