BURTNYAK, I. V.; MALYTS’KA, H. P. On the fundamental solution of the Cauchy problem for Kolmogorov systems of the second order. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 70, n. 8, p. 1107–1117, 2018. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1621. Acesso em: 5 dec. 2025.