@misc{indiciaec911438d2975,
  title = {PBDAT; a program for reduction of Pb-U-Th isotope data, for use with HP-86/87 microcomputers},
  author = {K.R. Ludwig},
  year = {1984},
  doi = {10.3133/ofr84113},
  url = {https://pubs.usgs.gov/publication/ofr84113},
  note = {Source identifier: ofr84113}
}