ZarubinA. N. “Integral Representation of a Solution of the Cauchy Problem for a Degenerating Hyperbolic Equation With Retarded Argument”. Ukrains’kyi Matematychnyi Zhurnal 49, no. 10 (October 25, 1997): 1332–1336. Accessed October 6, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5131.