On some class of partial difference equations admitting a zero-curvature   representation
  We show some classes of higher order partial difference equations admitting a zero-curvature representation and generalizing lattice potential KdV equation. We construct integrable hierarchies which, as we suppose, yield generalized symmetries for obtained class of partial difference equations. As a byproduct we also derive non-evolutionary differential-difference equations with their Lax pair representation which may be of potential interest. 
Andrei K. Svinin
nlin.SI math-ph math.MP