The Role of Conformal Symmetry in Abelian Bosonization of the Massive   Thirring Model
  We show equivalence between the massive Thirring model and the sine-Gordon theory by gauge fixing a wider gauge invariant theory in two different ways. The exact derivation of the equivalence hinges on the existence of an underlying conformal symmetry. Previous derivations were all perturbative in mass (althought to all orders). 
Aleksandar Bogojevic, Branislav Sazdovic (Institute of Physics) and   Olivera Miskovic (Vinca Institute)