@misc{indiciaedf763fd40d21,
  title = {Circumstances for Pluto-Charon mutual events in 1987},
  author = {Tholen, David J. and Buie, Marc W. and Swift, Catherine E.},
  year = {1987},
  url = {https://ntrs.nasa.gov/citations/19870040774},
  note = {Source identifier: 19870040774}
}