@misc{indiciae663df4c685ca,
  title = {The epoch state navigation filter},
  author = {Battin, R. H. and Croopnick, S. R. and Edwards, J. A.},
  year = {1977},
  url = {https://ntrs.nasa.gov/citations/19780048003},
  note = {Source identifier: 19780048003}
}