@misc{indiciaed331a1a6dcfa,
  title = {The magnetic field in the United States, 1985: Inclination chart},
  author = {N.W. Peddie and A.K. Zunde},
  year = {1988},
  doi = {10.3133/gp986i},
  url = {https://pubs.usgs.gov/publication/gp986I},
  note = {Source identifier: gp986I}
}