BOMAN, J. Smoothness of sums of convex sets with real analytic boundaries. MATHEMATICA SCANDINAVICA, [S. l.], v. 66, p. 225–230, 1990. DOI: 10.7146/math.scand.a-12306. Disponível em: https://www.mscand.dk/article/view/12306. Acesso em: 7 apr. 2025.