@misc{indiciaeed33384102cc,
  title = {Niobium and tantalum in the United States, exclusive of Alaska and Hawaii},
  author = {Raymond Laurence Parker},
  year = {1963},
  doi = {10.3133/mr36},
  url = {https://pubs.usgs.gov/publication/mr36},
  note = {Source identifier: mr36}
}