Symmetries and Integrability of Difference Equations - EuroConference on Analytic Difference Equations, Special Functions and Quantum Models on the Lattice. Helsinki, Finland; 19 - 24 June 2004. - http://www.esf.org/euresco/04/pc04185/
The Math Forum - A compilation of sites relating to Difference Equations. - http://mathforum.org/library/topics/difference_eq/