Xiang, Tian, and Rong Yuan. “Existence of Periodic Solutions for $p$-Laplacian Neutral Functional Equation With Multiple deviating arguments”. Topological Methods in Nonlinear Analysis 37, no. 2 (April 23, 2011): 235–258. Accessed March 28, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2011.013.