... ordernonlinear difference equations,” Journal of Mathematical Analysis and Applications, vol. 322, no. 2, pp.930–956, 2006.13 E. Thandapani and I. M. Arockiasamy, “Fourth-order nonlinear oscillations ... Applicable Analysis, vol. 59, no. 1–4, pp. 225–231, 1995.6 Z. Bai and H. Wang, On positive solutions of some nonlinear fourth-order beam equations,” Journal of Mathematical Analysis and Applications, ... Mathematical Analysis and Applications, vol. 326, no. 1, pp. 297–302, 2007.21 R. P. Agarwal, Difference Equations and Inequalities: Theory, Methods, and Applications, vol. 228 of Monographs and Textbooks...