Wong, P. J. Y. and Agarwal, R. P. (1997) “On the existence of positive solutions of higher order difference equations”, Topological Methods in Nonlinear Analysis, 10(2), pp. 339–351. Available at: https://apcz.umk.pl/TMNA/article/view/TMNA.1997.036 (Accessed: 22 July 2024).