@misc{indiciaeadbcc1b36fe0,
  title = {The magnetic field in the United States, 1990: Declination chart},
  author = {N.W. Peddie},
  year = {1992},
  doi = {10.3133/gp1002d},
  url = {https://pubs.usgs.gov/publication/gp1002D},
  note = {Source identifier: gp1002D}
}