@misc{indiciae82b3a1cfd567,
  title = {Localized sudden changes in the geomagnetic secular variation.},
  author = {L.R. Alldredge},
  year = {1987},
  doi = {10.5636/jgg.39.111},
  url = {https://pubs.usgs.gov/publication/70015171},
  note = {Source identifier: 70015171}
}