@misc{indiciae8cfc9f0e8105,
  title = {Interim geologic map of the Pepperell quadrangle, Massachusetts-New Hampshire},
  author = {G.R. Robinson},
  year = {1975},
  doi = {10.3133/ofr76266},
  url = {https://pubs.usgs.gov/publication/ofr76266},
  note = {Source identifier: ofr76266}
}