ÅHAG, Per; CEGRELL, Urban; CZYZ, Rafal. On Dirichlet’s principle and problem. Mathematica Scandinavica, Berkeley, CA, United States, v. 110, n. 2, p. 235–250, 2012. DOI: 10.7146/math.scand.a-15206. Disponível em: https://journals.msp.org/mscand/article/view/491. Acesso em: 24 jul. 2026.