Lagrangian Symmetries of Chern-Simons Theories
  This paper analyses the Noether symmetries and the corresponding conservation laws for Chern-Simons Lagrangians in dimension $d=3$. In particular, we find an expression for the superpotential of Chern-Simons gravity. As a by-product the general discussion of superpotentials for 3rd order natural and quasi-natural theories is also given. 
A. Borowiec, M. Ferraris and M. Francaviglia