@misc{indiciae36e053a54616,
  title = {Preliminary determination of epicenters; monthly listing; April-May 1999},
  author = {National Earthquake Information Center},
  year = {1999},
  doi = {10.3133/ofr99600b},
  url = {https://pubs.usgs.gov/publication/ofr99600B},
  note = {Source identifier: ofr99600B}
}