@misc{indiciae4d23deb2351d,
  title = {Determination of Radium-228 in Natural Waters},
  author = {Jesse O. Johnson},
  year = {1971},
  doi = {10.3133/wsp1696g},
  url = {https://pubs.usgs.gov/publication/wsp1696G},
  note = {Source identifier: wsp1696G}
}