@misc{indiciaeae8a25b61ce1,
  title = {Long-term variations in atomic nitrogen densities},
  author = {Engebretson, M. J. and Nygren, J. B.},
  year = {1982},
  url = {https://ntrs.nasa.gov/citations/19820038647},
  note = {Source identifier: 19820038647}
}