Kirilich VM, Firman TI. Problem without initial conditions for a countable semilinear hyperbolic system of first-order equations. Ukr. Mat. Zhurn. [Internet]. 2016Aug.25 [cited 2024Apr.19];68(8):1043-55. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/1900