@misc{indiciae080f9d1d4abf,
  title = {Ar40/Ar39 age spectrum dating of biotite from Middle Ordovician bentonites, eastern North America},
  author = {Michael J. Kunk and John F. Sutter},
  year = {1984},
  url = {https://pubs.usgs.gov/publication/70210406},
  note = {Source identifier: 70210406}
}