@misc{indiciaee8fa325f7cc6,
  title = {Preliminary report on some factors affecting shotpoint efficiency},
  author = {W. H. Jackson and J. H. Healy},
  year = {1964},
  doi = {10.3133/70039542},
  url = {https://pubs.usgs.gov/publication/70039542},
  note = {Source identifier: 70039542}
}