DARBINYAN, A.; TUMANYAN, A. On index stability of Noetherian differential operators in anisotropic Sobolev spaces . Eurasian Mathematical Journal, [S. l.], v. 10, n. 1, p. 09–15, 2019. DOI: 10.32523/2077-9879-2019-10-1-09-15. Disponível em: https://emj.enu.kz/index.php/main/article/view/136. Acesso em: 15 nov. 2026.