Lagrangian Formulation of the General Modified Chiral Model
  We present a Lagrangian formulation for the general modified chiral model. We use it to discuss the Hamiltonian formalism for this model and to derive the commutation relations for the chiral field. We look at some explicit examples and show that the Hamiltonian, containing a contribution involving a Wess-Zumino term, is conserved, as required. 
Theodora Ioannidou and Wojtek Zakrzewski