@misc{indiciaed2e738213597,
  title = {ISOPLOT version 2; a plotting and regression program for isotope geochemists, for use with HP series 200/300 computers},
  author = {K.R. Ludwig},
  year = {1988},
  doi = {10.3133/ofr87601},
  url = {https://pubs.usgs.gov/publication/ofr87601},
  note = {Source identifier: ofr87601}
}