TimokhaA. “On the Variational Statement of One Boundary-Value Problem With Free Interface”. Ukrains’kyi Matematychnyi Zhurnal 75, no. 8 (August 30, 2023): 1113 - 1118. Accessed July 25, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/7650.