@misc{indiciae47847f27ce1a,
  title = {Map showing thickness of material overlying principal clay unit, Broad Brook quadrangle, Connecticut},
  author = {W. H. Langer},
  year = {1973},
  doi = {10.3133/mf451d},
  url = {https://pubs.usgs.gov/publication/mf451D},
  note = {Source identifier: mf451D}
}