@misc{indiciaec5334793e39c,
  title = {Comet P/Encke's nongravitational force},
  author = {A'Hearn, Michael F. and Schleicher, David G.},
  year = {1988},
  url = {https://ntrs.nasa.gov/citations/19880060309},
  note = {Source identifier: 19880060309}
}