Models of Meson-Baryon Reactions in the Nucleon Resonance Region
  It is shown that most of the models for analyzing meson-baryon reactions in the nucleon resonance region can be derived from a Hamiltonian formulation of the problem. An extension of the coupled-channel approach to include $\pi\pi N$ channel is briefly described and some preliminary results for the $N^*(1535)$ excitation are presented. 
T.-S. H. Lee, A. Matsuyama, T. Sato