@misc{indiciae69b10fa27ddb,
  title = {Populations of the planet-crossing asteroids},
  author = {Eugene Merle Shoemaker and E. F. Helin and S. L. Gillett},
  year = {1976},
  url = {https://pubs.usgs.gov/publication/70226757},
  note = {Source identifier: 70226757}
}