Black hole solutions in four-dimensional topological gravity
  We study spherically symmetric solutions of a four-dimensional theory of gravity with a topological action, which was constructed as a Yang-Mills theory of the Poincar\'e group and can be considered a generalization to higher dimensions of well-known two-dimensional models. We also discuss the perturbative degrees of freedom and the properties of the theory under conformal transformations. 
S. Mignemi