An informal introduction to perturbations of matrices determined up to similarity or congruence. São Paulo Journal of Mathematical Sciences, [S. l.], v. 8, n. 1, p. 1–22, 2014. DOI: 10.11606/issn.2316-9028.v8i1p1-22. Disponível em: https://revistas.usp.br/spjournal/article/view/88610.. Acesso em: 3 maio. 2024.