@misc{indiciae166d0eba2659,
  title = {Contour map of the bedrock surface, Warren Quadrangle, Massachusetts},
  author = {C.J. Londquist},
  year = {1973},
  doi = {10.3133/mf541a},
  url = {https://pubs.usgs.gov/publication/mf541A},
  note = {Source identifier: mf541A}
}