@misc{indiciae86e3dd9acfa2,
  title = {Preparation and stable isotope determination of NBS-16 and NBS-17 carbon dioxide reference samples},
  author = {T.B. Coplen},
  year = {2002},
  doi = {10.1021/ac00251a050},
  url = {https://pubs.usgs.gov/publication/70011437},
  note = {Source identifier: 70011437}
}