The generalized Kondo lattice model and its spin-polaron implementation   for cuprates by projection method
  It is shown that the spin-fermion model found to be an effective low-energy implementation of the three-band Emery model after Wannier transformation of $p_x$- and $p_y$-orbitals in the oxygen ions subsystem is reduced to the generalized Kondo lattice model. Its essential feature is the presence of spin-correlated hoppings of the current carriers between distant cells. Numerical calculations of the spin-polaron spectrum demonstrate the important role of the distant hoppings. 
V.V. Val'kov, D.M. Dzebisashvili, A.F. Barabanov
cond-mat.supr-con cond-mat.str-el