@book{
  international1991iaea,
  title={X-ray and Gamma-ray Standards for Detector Calibration},
  series={TECDOC Series},
  number={619},
  year={1991},
  url={https://www.iaea.org/publications/875/x-ray-and-gamma-ray-standards-for-detector-calibration},
  publisher={INTERNATIONAL ATOMIC ENERGY AGENCY},
  address={Vienna}
}