@misc{indiciae23756dd42c9c,
  title = {Ionospheric composition: The seasonal anomaly explained},
  author = {Torr, D. G. and Richards, P. G. and Torr, M. R.},
  year = {1981},
  url = {https://ntrs.nasa.gov/citations/19810014990},
  note = {Source identifier: 19810014990}
}