@misc{indiciaeb2108c061fe6,
  title = {Hafnium content and hafnium-zirconium ratio in minerals and rocks},
  author = {Michael Fleischer},
  year = {1955},
  doi = {10.3133/b1021a},
  url = {https://pubs.usgs.gov/publication/b1021A},
  note = {Source identifier: b1021A}
}