Diffeomorphisms, Noether Charges and Canonical Formalism in 2D Dilaton   Gravity
  We carry out a parallel study of the covariant phase space and the conservation laws of local symmetries in two-dimensional dilaton gravity. Our analysis is based on the fact that the Lagrangian can be brought to a form that vanishes on-shell giving rise to a well-defined covariant potential for the symplectic current. We explicitly compute the symplectic structure and its potential and show that the requirement to be finite and independent of the Cauchy surface restricts the asymptotic symmetries. 
J. Navarro-Salas, M. Navarro and C. F. Talavera