@misc{indiciaec6cade665a89,
  title = {Transcription of geomagnetic variation data from sea data cassettes to tape using the HP9640A},
  author = {David V. Fitterman},
  year = {1981},
  doi = {10.3133/ofr8195},
  url = {https://pubs.usgs.gov/publication/ofr8195},
  note = {Source identifier: ofr8195}
}