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2. Ermolov, I.N. and Lange, Yu. V., Nerazrushayshchii kontrol'. Spravochnik v 7-mi tomakh (Nondestructive Testing. Handbook in 7 Volumes.), Klyuev, V.V., Ed., vol. 3: Ultrasonic Testing, Moscow: Mashinostroenie, 2004.
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