1. Atici, F. M. and Cabada, A. (2003). Existence and uniqueness results for
discrete second-order periodic boundary value problems, Comput. Math.
Appl. 45, 1417-1427.
2.Atici, F. M. and Guseinov, G. S. (1999). Positive periodic solutions for
nonlinear difference equations with J. periodic coefficients, Math. Anal.
Appl. 232, 166-182.
3.Bonanno, G. and Candito, P. (2009). Infinitely many solutions for a class
of discrete non-linear boundary value problems, Appl. Anal. 884, 605-
616.
4. Bonanno, G. and Candito, P. (2009). Nonlinear difference equations
investigated via critical point methods, Nonlinear Anal. TMA 70, 3180-
3186.
5.Cabada, A., Iannizzotto, A. and Tersian, S. (2009). Multiple solutions for
discrete boundary value problem, J. Math. Anal. Appl. 356, 418-428.