ANDERSSON, Rolf. Unbounded Soboleff Regions. Mathematica Scandinavica, Berkeley, CA, United States, v. 13, p. 75–89, 1963. DOI: 10.7146/math.scand.a-10690. Disponível em: https://journals.msp.org/mscand/article/view/2635. Acesso em: 25 jul. 2026.