Assymptotic solutions in the ultrasonic corrosion control. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 88, p. 341–346, 1996. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/393. Acesso em: 11 jan. 2026.