@misc{indiciae0fada4455a1e,
  title = {Data assimilation of ground GPG total electron content into a physics-based ionosheric model by use of the Kalman filter},
  author = {Hajj, G. A. and Wilson, B. D. and Wang, C. and Pi, X. and Rosen, I. G.},
  year = {2004},
  url = {https://ntrs.nasa.gov/citations/20060040134},
  note = {Source identifier: 20060040134}
}