A Counterexample in the Theory of Coerciveness for Elliptic Systems. Journal of Partial Differential Equations, [S. l.], v. 2, n. 3, p. 79–82, 1989. Disponível em: https://www.global-sci.com/index.php/jpde/article/view/3629. Acesso em: 5 dec. 2025.