HELGASON, S. A characterization of the intersection of $L^1$-spaces. MATHEMATICA SCANDINAVICA, [S. l.], v. 4, p. 5–8, 1956. DOI: 10.7146/math.scand.a-10450. Disponível em: https://www.mscand.dk/article/view/10450. Acesso em: 8 may. 2024.