@misc{indiciae909f1a13969d,
  title = {Programs for filing and plotting U-Pb isotope data for concordia diagrams, using an HP-9830 computer and HP-9862 plotter},
  author = {K.R. Ludwig},
  year = {1982},
  doi = {10.3133/ofr82386},
  url = {https://pubs.usgs.gov/publication/ofr82386},
  note = {Source identifier: ofr82386}
}