@misc{indiciae15dfd4fb06e3,
  title = {Glauconite from the Precambrian belt series, Montana},
  author = {R. A. Gulbrandsen and S. S. Goldich and H.H. Thomas},
  year = {1963},
  doi = {10.1126/science.140.3565.390},
  url = {https://pubs.usgs.gov/publication/70010685},
  note = {Source identifier: 70010685}
}