BERG, Christian. Semi-groupes de moments. Mathematica Scandinavica, Berkeley, CA, United States, v. 54, p. 177–182, 1984. DOI: 10.7146/math.scand.a-12051. Disponível em: https://journals.msp.org/mscand/article/view/1579. Acesso em: 25 jul. 2026.