MIKHAILETS, V. A.; MURACH, A. A. Extended Sobolev Scale and Elliptic Operators. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 65, n. 3, p. 392–404, 2013. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2426. Acesso em: 5 dec. 2025.