LOS, V. N. Sobolev’s problem for general elliptic systems of Lere-Volevich’s structure. Methods of Functional Analysis and Topology, [S. l.], v. 8, n. 4, p. 58–71, 2002. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/200. Acesso em: 18 dec. 2025.