@misc{indiciae4fe41ea5ce86,
  title = {Multi-Cone Model for Estimating GPS Ionospheric Delays},
  author = {Sparks, Lawrence and Komjathy, Attila and Mannucci, Anthony},
  year = {2009},
  url = {https://ntrs.nasa.gov/citations/20090035904},
  note = {Source identifier: 20090035904}
}