Zernov, A. E., & Kuzina, Y. V. (2003). Qualitative Investigation of the Singular Cauchy Problem <em class="a-plus-plus">F</em>(<em class="a-plus-plus">t</em>, <em class="a-plus-plus">x</em>, <em class="a-plus-plus">x</em>′) = 0, <em class="a-plus-plus">x</em&gt;(0) = 0. Ukrains’kyi Matematychnyi Zhurnal, 55(12), 1720-1723. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/4033