@misc{indiciae85b633c1047b,
  title = {The magnetic charts of the United States for Epoch 1975},
  author = {Eugene B. Fabiano and W. J. Jones and Norman W. Peddie},
  year = {1979},
  doi = {10.3133/cir810},
  url = {https://pubs.usgs.gov/publication/cir810},
  note = {Source identifier: cir810}
}