1. ASME Boiler and Pressure Vessel Code Section XI: Rules for in-service inspection of nuclear power plant components.
2. API Recommended Practice 579: Fitness for service.
3. H. Harper, Detection of Defects and Assessment of Serviceability. Mater. Sci. Eng. 3, UNESCO.
4. Acceptance Levels of Weld Defects for Fatigue Service;Boulton;Welding Res. Suppl.,1977
5. Ultrasonic testing of materials at Level II, IAEA TECDOC-462.