共 4 条
- [2] Wong P J, Agarwal R P.On the existence of solutions of singular boundary value problems for higher order difference equations[K].Nonlinear Analysis,1997
- [3] GUO D.The order methods in nonlinear anlysis[K].Techical and Science Press,2000
- [4] AGARWAL PR,O’Regan D.Nonpositone discrete boundary value problems[K].Nonlinear Anal,2000