@misc{indiciae36d8ad0e5e01,
  title = {Users manual for the hypocenter plotting program GPP3},
  author = {John C. Lahr},
  year = {1975},
  doi = {10.3133/ofr75599},
  url = {https://pubs.usgs.gov/publication/ofr75599},
  note = {Source identifier: ofr75599}
}