SlyusarchukV. Y. “Conditions of Existence of Bounded and Almost Periodic Solutions of nonlinear differential Equation With Perturbations of Solutions”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 68, no. 9, Sept. 2016, pp. 1286-9, http://umj.imath.kiev.ua/index.php/umj/article/view/1921.