@misc{indiciae3a2b4bea77cd,
  title = {Earth-approaching asteroids: Populations, origin, and compositional types},
  author = {Shoemaker, E. M. and Helin, E. F.},
  year = {1978},
  url = {https://ntrs.nasa.gov/citations/19780021074},
  note = {Source identifier: 19780021074}
}