@misc{indiciae4c83dfa2e595,
  title = {Geochemical association of niobium (columbium) and titanium and its geological and economic significance},
  author = {Michael Fleischer and K. J. Murata and Janet D. Fletcher and Perry F. Narten},
  year = {1952},
  doi = {10.3133/cir225},
  url = {https://pubs.usgs.gov/publication/cir225},
  note = {Source identifier: cir225}
}