@misc{indiciae1e2ee4e2b426,
  title = {Comet Shoemaker-Levy 9: An Active Comet},
  author = {Rettig, Terrence W. and Hahn, Joseph M.},
  year = {1997},
  url = {https://ntrs.nasa.gov/citations/19980202398},
  note = {Source identifier: 19980202398}
}