PelyukhG. P. “On Global Solutions of Systems of Nonlinear Functional Differential Equations With Deviating Argument Dependent on Unknown Functions”. Ukrains’kyi Matematychnyi Zhurnal 54, no. 3 (March 25, 2002): 402-407. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4076.