@misc{indiciae303a982ea3e5,
  title = {Survey Data for Geomagnetic Field Modelling},
  author = {Barraclough, D. R. and Macmillan, S.},
  year = {1992},
  url = {https://ntrs.nasa.gov/citations/19920019380},
  note = {Source identifier: 19920019380}
}