@article{ETNA_2007__27__a11,
     author = {Cabada,  Alberto},
     title = {The method of lower and upper solutions for periodic and anti-periodic difference equations},
     journal = {Electronic transactions on numerical analysis},
     pages = {13--25},
     year = {2007},
     volume = {27},
     zbl = {1171.39301},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2007__27__a11/}
}