WINTNER, Aurel. On an absolute constant pertaining to Cauchy’s "principal moduli" in bounded power series. Mathematica Scandinavica, Berkeley, CA, United States, v. 4, p. 108–112, 1956. DOI: 10.7146/math.scand.a-10459. Disponível em: https://journals.msp.org/mscand/article/view/2867. Acesso em: 8 sep. 2026.