@book{
      international1972iaea,
      title={Tracer Studies on Non-protein Nitrogen for Ruminants},
      author={ },
      series={entity},
      number={ },
      year={1972},
      isbn={92-0-111072-3 },
      url={/publications/3056/tracer-studies-on-non-protein-nitrogen-for-ruminants },
      publisher={INTERNATIONAL ATOMIC ENERGY AGENCY },
      address={Vienna}
    }