00561naa#a2200193#i#450# EN\\bibl\9540 20241011154816.5 1609-3178 20151216b2015####ek#y0engy0150####ca RUS RU Procedure of NDT Instruments Qualification Tests. Classification of Ultrasonic Testing Devices Journal article Saint-Petersburg LLC SVEN 2015 3 с. Journal article local Okunev Denis Tulskiy Mikhail Litvinov Ivan naukaru.ru