ENGEL, Zbigniew. K.U. INGARD, Notes on Sound Absorption Technology, Noise Control Foundation, Poughkeepsie. Archives of Acoustics, [S. l.], v. 21, n. 1, p. 115–117, 2014. Disponível em: https://acoustics3.ippt.pan.pl/index.php/aa/article/view/984. Acesso em: 25 apr. 2025.