T VIDYA. Recent Developments in Spectral Theory: A Functional Analysis Approach to Operators on Hilbert Spaces. Universal Research Reports, [S. l.], v. 10, n. 3, p. 219–232, 2023. DOI: 10.36676/urr.v10.i3.1585. Disponível em: https://urr.shodhsagar.com/index.php/j/article/view/1585. Acesso em: 4 sep. 2025.