Vector-Chiral Equivalence in Null Gauged WZNW Theory
  We consider the standard vector and chiral gauged WZNW models by their gauged maximal null subgroups and show that they can be mapped to each other by a special transformation. We give an explicit expression for the map in the case of the classical Lie groups $ A_N $, $ B_N $, $ C_N $, $ D_N $, and note its connection with the duality map for the Riemmanian globally symmetric spaces. 
F. Ardalan, A. M. Ghezelbash