On the problem of Unicity in Einstein-Sciama-Kibble Theory
  We consider the ESK theory, based on the principle for which the space is filled with matter fields in such a way that Cartan torsion is spin; in the geometry in which Cartan torsion tensor is completely antisymmetric, spin has to be completely antisymmetric: we will show how the complete antisymmetry of spin constraints the form of possible matter field theories as to allow the special case of the simplest one solely, all other most general cases being excluded. 
Luca Fabbri