1. American Society of Mechanical Engineers. (2015). ASME boiler and pressure vessel code. Ultrasonic examination methods for materials (ASME BPVC.V-2015 Article 5, p. 400:2015). ASME Boiler and Pressure Vessel Committee.
2. International Organization for Standardization. (2014a). Non-destructive testing - ultrasonic testing - general principles (ISO Standard No. 168102014). http://ecommerce.sist.si/
3. International Organization for Standardization. (2014b). Non-destructive testing - ultrasonic testing - characterization and sizing of discontinuities (ISO Standard No. 16827. 2014). http://ecommerce.sist.si/