LAPRUS, W.; DANICKI, E. Singularities of the planar green function in the spectral domain. Archives of Acoustics, [S. l.], v. 22, n. 2, p. 169–178, 1997. Disponível em: https://acoustics.ippt.pan.pl/index.php/aa/article/view/947. Acesso em: 25 feb. 2026.