@misc{indiciaecf1d11a097d7,
  title = {Bedrock geologic map of the Ludlow quadrangle, Hampden and Hampshire Counties, south-central Massachusetts},
  author = {Gerhard W. Leo and Peter Robinson and David Joseph Hall},
  year = {1977},
  doi = {10.3133/gq1353},
  url = {https://pubs.usgs.gov/publication/gq1353},
  note = {Source identifier: gq1353}
}