@misc{indiciae13b4916042fa,
  title = {Early Silurian graptolites from southeastern Alaska and their correlation with graptolitic sequences in North America and the Arctic},
  author = {Michael Churkin and Claire Carter},
  year = {1970},
  doi = {10.3133/pp653},
  url = {https://pubs.usgs.gov/publication/pp653},
  note = {Source identifier: pp653}
}