KalitaE. A. “Partial Regularity of Traces of Solutions of Higher-Order Nonlinear Elliptic Systems”. Ukrains’kyi Matematychnyi Zhurnal 45, no. 11 (November 25, 1993): 1495–1502. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5956.