ZhaoH. Y. “A Note on Iterative Solutions of an Iterative Functional Differential Equation”. Ukrains’kyi Matematychnyi Zhurnal 72, no. 11 (November 20, 2020): 1564-1574. Accessed November 29, 2020. http://umj.imath.kiev.ua/index.php/umj/article/view/6034.