@misc{indiciae71fcf5388157,
  title = {Microscopic studies of uraniferous coal deposits--a progress report},
  author = {James M. Schopf and Ralph J. Gray},
  year = {1954},
  doi = {10.3133/tei408},
  url = {https://pubs.usgs.gov/publication/tei408},
  note = {Source identifier: tei408}
}