@misc{indiciae84ab3a3cf453,
  title = {Bedrock geologic map of the Grafton quadrangle, Worcester County, Massachusetts},
  author = {Gregory J. Walsh and John N. Aleinikoff and Michael J. Dorais},
  year = {2011},
  doi = {10.3133/sim3171},
  url = {https://pubs.usgs.gov/publication/sim3171},
  note = {Source identifier: sim3171}
}