@misc{indiciaea214db0e8beb,
  title = {Some problems of the Rocky Mountain phosphate field},
  author = {George R. Mansfield},
  year = {1931},
  doi = {10.2113/gsecongeo.26.4.353},
  url = {https://pubs.usgs.gov/publication/70217851},
  note = {Source identifier: 70217851}
}