BISTRÖM, P.; JARAMILLO, Jesus A. $C^\infty$-Bounding Sets and Compactness. MATHEMATICA SCANDINAVICA, [S. l.], v. 75, p. 82–86, 1994. DOI: 10.7146/math.scand.a-12504. Disponível em: https://tidsskrift.dk/math/article/view/12504. Acesso em: 14 aug. 2026.