Discretization of hyperbolic type Darboux integrable equations   preserving integrability
  A method of integrable discretization of the Liouville type nonlinear partial differential equations is suggested based on integrals. New examples of discrete Liouville type models are presented. 
Ismagil Habibullin, Natalya Zheltukhina and Alfia Sakieva
nlin.SI