RASULOV, T.; DILMURODOV, E. B. Estimates for the Bounds of the Essential Spectrum of a 2 × 2 Operator Matrix. Contemporary Mathematics, [S. l.], v. 1, n. 4, p. 170–186, 2020. DOI: 10.37256/cm.142020409. Disponível em: https://ojs.wiserpub.com/index.php/CM/article/view/409. Acesso em: 25 apr. 2024.