@misc{indiciae1d1861a91bab,
  title = {Cometary orbital evolution in the outer planetary region},
  author = {Manara, Allesandro and Valsecchi, G. B.},
  year = {1992},
  url = {https://ntrs.nasa.gov/citations/19930010015},
  note = {Source identifier: 19930010015}
}