ZernovA. E., and MeleshkoT. V. “On the Asymptotic Behavior of Solutions of a Singular Cauchy Problem”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 53, no. 9, Sept. 2001, pp. 1194-03, https://umj.imath.kiev.ua/index.php/umj/article/view/4337.