ESSÉN, Matts; LEWIS, John L. The Generalized Ahlfors-Heins Theorem in Certain $d$-Dimensional Cones. Mathematica Scandinavica, Berkeley, CA, United States, v. 33, p. 113–129, 1973. DOI: 10.7146/math.scand.a-11477. Disponível em: https://journals.msp.org/mscand/article/view/2188. Acesso em: 25 jul. 2026.