WANG, C. Y. Biharmonic Green’s functions and biharmonic degeneracy. MATHEMATICA SCANDINAVICA, [S. l.], v. 37, p. 122–128, 1975. DOI: 10.7146/math.scand.a-11594. Disponível em: https://www.mscand.dk/article/view/11594. Acesso em: 5 may. 2024.