@article{PORMA_1993__50_2_115814,
     author = {Yan, Jurang},
     title = {Oscillation results for difference equations with delays},
     journal = {Portugaliae mathematica},
     pages = {129--138},
     publisher = {mathdoc},
     volume = {50},
     number = {2},
     year = {1993},
     mrnumber = {1244492},
     zbl = {0799.39003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1993__50_2_115814/}
}