WANG, C. Y. Biharmonic Green’s Functions and Quasiharmonic Degeneracy. MATHEMATICA SCANDINAVICA, [S. l.], v. 35, p. 38–42, 1974. DOI: 10.7146/math.scand.a-11533. Disponível em: https://www.mscand.dk/article/view/11533. Acesso em: 6 may. 2024.