BEURLING, Arne. A theorem on functions defined on a semi-group. Mathematica Scandinavica, Berkeley, CA, United States, v. 1, p. 127–130, 1953. DOI: 10.7146/math.scand.a-10372. Disponível em: https://journals.msp.org/mscand/article/view/2951. Acesso em: 25 jul. 2026.