@misc{indiciaec88c8221e6a7,
  title = {Fission-track dating of lower Paleozoic volcanic ashes in British stratotypes},
  author = {Reuben James Ross and Charles W. Naeser and Glen Arthur Izett},
  year = {1977},
  doi = {10.3133/ofr77348},
  url = {https://pubs.usgs.gov/publication/ofr77348},
  note = {Source identifier: ofr77348}
}