@misc{indiciae6441cbaf17e5,
  title = {A discussion of sources and description of the Earth's magnetic field and its secular variations},
  author = {Leroy Romney Alldredge and Charles O. Stearns},
  year = {1974},
  doi = {10.5636/jgg.26.393},
  url = {https://pubs.usgs.gov/publication/70246994},
  note = {Source identifier: 70246994}
}