Some New Results on Strictly Singular Operators and Pre- Compact Operators: Characteristics and implications of simply singular operators. Journal of Advances and Scholarly Researches in Allied Education, [S. l.], v. 16, n. 9, p. 981–985, 2019. Disponível em: https://ignited.in/index.php/jasrae/article/view/12337.. Acesso em: 9 jul. 2025.