POPOV, A.; MICHOVSKI, M. Assymptotic solutions in the ultrasonic corrosion control. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 88, p. 341–346, 1996. Disponível em: https://ftl5.uni-sofia.bg/index.php/fmi/article/view/393. Acesso em: 4 dec. 2024.