@misc{indiciae12946dd9739d,
  title = {Observation of a "front" of regional metamorphism},
  author = {Rene Perrin and Marcel Roubault and S. H. Britt},
  year = {1953},
  doi = {10.3133/ofr5432},
  url = {https://pubs.usgs.gov/publication/ofr5432},
  note = {Source identifier: ofr5432}
}