@misc{indiciae91b639a06f1e,
  title = {Foreshock seismic-energy-release functions; tools for estimating time and magnitude of main shocks},
  author = {D. J. Varnes},
  year = {1987},
  doi = {10.3133/ofr87429},
  url = {https://pubs.usgs.gov/publication/ofr87429},
  note = {Source identifier: ofr87429}
}