The BF Formalism for Yang-Mills Theory and the `t Hooft Algebra
  The deformation of a topological field theory, namely the pure BF theory, gives the first order formulation of Yang-Mills theory; Feynman rules are given and the standard uv-behaviour is recovered. In this formulation new non local observables can be introduced following the topological theory and giving an explicit realization of `t Hooft algebra. 
Maurizio Martellini and Mauro Zeni