Savchenko, L. I. “On the Solution Estimation of the First Boundary Value Problem for the Quasi-Linear Systems of Differential Equations of Parabolic Type ”.
Ukrains’kyi Matematychnyi Zhurnal 23, no. 3 (April 26, 1971): 421–428. Accessed April 7, 2025.
https://umj.imath.kiev.ua/index.php/umj/article/view/8574.