@misc{indiciaea8deb9aaf76a,
  title = {Tourmaline in Appalachian - Caledonian massive sulphide deposits and its exploration significance.},
  author = {J. F. Slack},
  year = {1982},
  url = {https://pubs.usgs.gov/publication/70011895},
  note = {Source identifier: 70011895}
}