%0 Journal Article %A Smith, B. %T Oscillation and nonoscillation theorems for third order quasi-adjoint difference equations %J Portugaliae mathematica %D 1988 %P 229-243 %V 45 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/PORMA_1988__45_3_115627/ %G en %F PORMA_1988__45_3_115627