BJÖRUP, K. On Inequalities of Poincaré’s Type. MATHEMATICA SCANDINAVICA, [S. l.], v. 8, p. 157–167, 1960. DOI: 10.7146/math.scand.a-10604. Disponível em: https://www.mscand.dk/article/view/10604. Acesso em: 29 apr. 2024.