@misc{indiciae8523df5effdb,
  title = {A review of recent activity in the United States.},
  author = {H.L. Cannon and W.L. Petrie},
  year = {1979},
  doi = {10.1098/rstb.1979.0096},
  url = {https://pubs.usgs.gov/publication/70012292},
  note = {Source identifier: 70012292}
}