1. Oscillation and nonoscillation for second-order linear difference equations;Zhang;Computers Math. Applic.,2000
2. Oscillation criteria for second order difference equation;Cheng;Funkcialaj Ekvacioj,1991
3. Spectral analysis of second order difference equations;Hinton;J. Math. Anal. Appl.,1981
4. Oscillation criteria and comparison theorems foe delay difference equations;Zhang;Fasciculi Mathematici,1995