Ivasyshen, S. D., and V. A. Litovchenko. “Cauchy Problem for a Class of Degenerate Kolmogorov-Type Parabolic Equations With Nonpositive Genus”. Ukrains’kyi Matematychnyi Zhurnal 62, no. 10 (October 25, 2010): 1330–1350. Accessed April 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2958.