RAVAUD, Romain; LEMARQUAND, Guy; LEMARQUAND, Valérie; DEPOLLIER, Claude. Ironless Loudspeakers with Ferrofluid Seals. Archives of Acoustics, [S. l.], v. 33, n. 4(S), p. 53–58, 2008. Disponível em: https://acoustics3.ippt.pan.pl/index.php/aa/article/view/835. Acesso em: 26 apr. 2025.