PIRANIAN, George. Bounded Radial Variation and Divergence of Power Series. Mathematica Scandinavica, Berkeley, CA, United States, v. 18, p. 93–96, 1966. DOI: 10.7146/math.scand.a-10783. Disponível em: https://journals.msp.org/mscand/article/view/2521. Acesso em: 25 jul. 2026.