Remarks on Quantum Aspects of 3D-Gravity in the First-Order Formalism
  In this paper, we reassess the issue of working out the propagators and identifying the spectrum of excitations associated to the vielbein and spin connection of (1+2)-D gravity in the presence of torsion by adopting the first-order formulation. A number of peculiarities is pointed out whenever the Chern-Simons term is taken into account along with the possible bilinear terms in the torsion tensor. We present a procedure to derive the full set of propagators, based on a set of spin-type operators, and we discuss under which conditions the pole of these tree-level 2-point functions correspond to physical excitations. 
L M de Moraes, J A Helayel-Neto, V J Vasquez Otoya