Nonperturbative calculations in SU(3) gauge theory
  An approximate technique for performing nonperturbative calculations in quantum SU(3) gauge theory is presented. One aspect of this nonperturbative method is the breaking down $SU(3) \to SU(2) + coset$. The procedure also uses some aspects of an old method by Heisenberg to calculate the n-point Green's function of strongly interacting, non-linear fields. Using these ideas we give approximate calculations of the 2 and 4-points Green's functions. 
Vladimir Dzhunushaliev, Douglas Singleton and Tatyana Nikulicheva