Popov, A. and Michovski, M. (1996) “Assymptotic solutions in the ultrasonic corrosion control”, Ann. Sofia Univ. Fac. Math. and Inf, 88, pp. 341–346. Available at: https://ftl5.uni-sofia.bg/index.php/fmi/article/view/393 (Accessed: 4 December 2024).