@misc{indiciae122cbcb4ab3d,
  title = {The variability of ionospheric parameters},
  author = {Benkova, N. P. and Sukhodolskaya, A. N.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19670028895},
  note = {Source identifier: 19670028895}
}