KapustyanV. E. “Asymptotic Analysis of a Bounded Control in Optimal Elliptic Problems”. Ukrains’kyi Matematychnyi Zhurnal 45, no. 8 (August 25, 1993): 1072–1083. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5902.