1. Difference Equations;Kelley,1991
2. Difference Equations and Inequalities;Agarwal,1992
3. An Introduction to Difference Equations;Elaydi,1999
4. Global Behavior of Nonlinear Difference Equations of Higher-Order with Applications;Kocic,1993
5. Theory of Difference Equations: Numerical Methods and Applications;Lakshmikantham,1988