P. Selvakumar, and A. Murugesan. “Necessary and Sufficient Conditions for Oscillation of Solutions to Second-Order Non-Linear Difference Equations With Delay Argument”. Malaya Journal of Matematik 9, no. 01 (January 1, 2021): 1170–1175. Accessed July 16, 2024. https://www.malayajournal.org/index.php/mjm/article/view/1243.