Zhestkov S. V. and Ermolaev E. A. (1992) “One algebraic method to study stability of linear normal systems in partial derivatives”, Ukrains’kyi Matematychnyi Zhurnal, 44(4), pp. 480-489. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/7889 (Accessed: 27July2024).