SKRZYPCZYK, Jerzy; WINKLER-SKALNA, A. Sound wave propagation problems new perturbation methodology. Archives of Acoustics, [S. l.], v. 31, n. 4(S), p. 115–121, 2014. Disponível em: https://acoustics.ippt.pan.pl/index.php/aa/article/view/1331. Acesso em: 4 aug. 2025.