YAP, Leonard Y. H. On the Impossibility of Representing Certain Functions by Convolutions. MATHEMATICA SCANDINAVICA, [S. l.], v. 26, p. 132–140, 1970. DOI: 10.7146/math.scand.a-10972. Disponível em: https://tidsskrift.dk/math/article/view/10972. Acesso em: 14 aug. 2026.