GARDING, L. Dirichlet’s problem for linear elliptic partial differential equations. MATHEMATICA SCANDINAVICA, [S. l.], v. 1, p. 55–72, 1953. DOI: 10.7146/math.scand.a-10364. Disponível em: https://www.mscand.dk/article/view/10364. Acesso em: 2 may. 2024.