@book{
  international1991iaea,
  title={Training Guidelines in Non-destructive Testing Techniques},
  series={TECDOC Series},
  number={628},
  year={1991},
  url={https://www.iaea.org/publications/884/training-guidelines-in-non-destructive-testing-techniques},
  publisher={INTERNATIONAL ATOMIC ENERGY AGENCY},
  address={Vienna}
}