V. E. Kapustyan, “Asymptotics of locally constrained control in optimal parabolic problems”, Ukr. Mat. Zhurn., vol. 48, no. 1, pp. 50–56, Jan. 1996, Accessed: Apr. 13, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5362