@misc{indiciaed361543d86b0,
  title = {Geomagnetic polarity epochs: age and duration of the olduvai normal polarity event},
  author = {C. S. Grommé and R. L. Hay},
  year = {1971},
  doi = {10.1016/0012-821x(71)90004-5},
  url = {https://pubs.usgs.gov/publication/70010277},
  note = {Source identifier: 70010277}
}