@misc{1156726,
  author = {A H Brady},
  title = {Calculation of sunrise and sunset times at ionospheric heights along a great circle path:},
  year = {1964},
  month = {1964-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NBS.TN.209},
  language = {en},
}