DUDKIN, M. E.; VDOVENKO, T. On extensions of linear functionals with applications to non-symmetrically singular perturbations. Methods of Functional Analysis and Topology, [S. l.], v. 24, n. 3, p. 193–206, 2018. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/696. Acesso em: 15 dec. 2025.