@misc{indiciae17dc6a11faa3,
  title = {Aeromagnetic map of the Reading quadrangle, Middlesex and Essex Counties, Massachusetts},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1970},
  doi = {10.3133/gp721},
  url = {https://pubs.usgs.gov/publication/gp721},
  note = {Source identifier: gp721}
}