@misc{indiciaeed3182915c3f,
  title = {Phosphate exploration in Colombia - a case history},
  author = {James Bachelder Cathcart},
  year = {1967},
  doi = {10.3133/ofr6742},
  url = {https://pubs.usgs.gov/publication/ofr6742},
  note = {Source identifier: ofr6742}
}