NYALUKE, K.W; OKELO, N.B; ONGATI, O. Orthogonal Idempotents and Continuous Fredholm Operators under Perturbations. International Journal of Modern Computation, Information and Communication Technology, [S. l.], v. 3, n. 5 & 6, p. 42–47, 2020. DOI: 10.65000/gx443b83. Disponível em: https://gjpublications.com/index.php/IJMCICT/article/view/54. Acesso em: 22 oct. 2025.