Litovchenko, V. A. “Hyperbolic Systems in Gelfand and Shilov Spaces”. Ukrains’kyi Matematychnyi Zhurnal 71, no. 10 (October 25, 2019): 1360-1373. Accessed March 28, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/1520.