PlotkinY. D., and TurbinA. F. “Asymptotic Integration of a Singularly Perturbed Quasilinear Cauchy Problem in a Banach Space”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 51, no. 8, Aug. 1999, pp. 1077–1086, https://umj.imath.kiev.ua/index.php/umj/article/view/4698.