@misc{indiciae275378b60c53,
  title = {On modeling magnetic fields on a sphere with dipoles and quadrupoles},
  author = {David Goodwin Knapp},
  year = {1980},
  doi = {10.3133/pp1118},
  url = {https://pubs.usgs.gov/publication/pp1118},
  note = {Source identifier: pp1118}
}