RITTY, A. Directional Loudspeaker Using a Parametric Array. Acta Polytechnica, Prague, Czech Republic, v. 46, n. 4, 2006. DOI: 10.14311/862. Disponível em: https://ojs.cvut.cz/ojs/index.php/ap/article/view/862. Acesso em: 3 apr. 2025.