NAKAI, M.; SARIO, L. A Property of Biharmonic Functions with Dirichlet Finite Laplacians. MATHEMATICA SCANDINAVICA, [S. l.], v. 29, p. 307–316, 1971. DOI: 10.7146/math.scand.a-11057. Disponível em: https://www.mscand.dk/article/view/11057. Acesso em: 6 may. 2024.