Pelyukh, G.P. and Samoilenko, A.M. (1994) “Solutions of systems of nonlinear functional-differential equations bounded in the entire real axis and their properties”, Ukrains’kyi Matematychnyi Zhurnal, 46(6), pp. 737–747. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5701 (Accessed: 5 December 2025).