FUGLEDE, Bent. The Symmetric Normal Derivative of a Subharmonic Function II. Mathematica Scandinavica, Berkeley, CA, United States, v. 12, p. 129–146, 1963. DOI: 10.7146/math.scand.a-10677. Disponível em: https://journals.msp.org/mscand/article/view/2645. Acesso em: 25 jul. 2026.