@misc{indiciae85b8f2ff6d9c,
  title = {Aeromagnetic map of the Hudson quadrangle, Worcester and Middlesex Counties, Massachusetts},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1970},
  doi = {10.3133/gp704},
  url = {https://pubs.usgs.gov/publication/gp704},
  note = {Source identifier: gp704}
}