On the origin of superselection rules and different solutions of   Thirring model
  The normal forms of different one- and two- parametric solutions of Thirring model are connected with each other by making use of generalized conformal shift transformations. A new alternative sources of superselection rules are shown and the ways of spontaneous symmetry breaking are discussed. 
S.E. Korenblit, V.V. Semenov
hep-th