1. Existence Theory for Nonlinear Ordinary Differential Equations;O'Regan,1997
2. Advanced Topics in Difference Equations;Agarwal,1997
3. On the existence of positive solutions to higher order difference equations;Agarwal;Top. Methods in Nonl. Anal.,1997
4. Boundary value problems for discrete equations;Agarwal;Appl. Math. Lett.,1997
5. Difference Equations and Inequalities;Agarwal,1992