• Keevisõmbluste mittepurustav katsetamine [Võrguteavik] : katsetamine ultraheliga. Meetodid, katsetamise tasemed ja hindamine = Non-destructive testing of welds : ultrasonic testing. Techniques, testing levels, and assessment (ISO 17640:2010)2015 http://www.ester.ee/record=b4456155*est