Czernous, W. “Generalized Solutions of Mixed Problems for First-Order Partial Functional Differential Equations”.
Ukrains’kyi Matematychnyi Zhurnal 58, no. 6 (June 25, 2006): 804–828. Accessed April 27, 2025.
https://umj.imath.kiev.ua/index.php/umj/article/view/3497.