LIU, Zhenyu. Design and Testing of a Piezoelectric Ultrasonic Transducer. International Journal of Mechanical and Electrical Engineering, London, U.K., v. 6, n. 3, p. 28–33, 2025. DOI: 10.62051/ijmee.v6n3.04. Disponível em: https://wepub.org/index.php/IJMEE/article/view/5628. Acesso em: 25 jul. 2026.