P. SELVAKUMAR; A. MURUGESAN. Necessary and sufficient conditions for oscillation of solutions to second-order non-linear difference equations with delay argument. Malaya Journal of Matematik, India, v. 9, n. 01, p. 1170–1175, 2021. Disponível em: https://www.malayajournal.org/index.php/mjm/article/view/1243. Acesso em: 16 jul. 2024.