VUORINEN, Matti. Cluster sets and boundary behavior of quasiregular mappings. Mathematica Scandinavica, Berkeley, CA, United States, v. 45, p. 267–281, 1979. DOI: 10.7146/math.scand.a-11842. Disponível em: https://journals.msp.org/mscand/article/view/1804. Acesso em: 25 jul. 2026.