ÅHAG, P.; CEGRELL, U.; CZYZ, R. On Dirichlet’s principle and problem. MATHEMATICA SCANDINAVICA, [S. l.], v. 110, n. 2, p. 235–250, 2012. DOI: 10.7146/math.scand.a-15206. Disponível em: https://www.mscand.dk/article/view/15206. Acesso em: 27 apr. 2024.