A discussion on the most general torsion-gravity with electrodynamics   for Dirac spinor matter fields
  We consider the most general torsional completion of gravitation together with electrodynamics for the Dirac spinorial material fields, and we show that consistency arguments constrain torsion to be completely antisymmetric and the dynamics to be parity-invariant and described by actions that are either least-order derivative or renormalizable. 
Luca Fabbri
gr-qc