BELTIÅ£ÄƑ, Ingrid; CORNEAN, Horia D. On a Theorem of Arne Persson. CUBO, A Mathematical Journal, [S. l.], v. 6, n. 2, p. 1–14, 2004. Disponível em: https://cubo.ufro.cl/index.php/cubo/article/view/1637. Acesso em: 12 oct. 2025.