@misc{indiciae0e732f7743d3,
  title = {Aeromagnetic map of the Ludlow quadrangle, Hampden and Hampshire Counties, Massachusetts},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1968},
  doi = {10.3133/gp619},
  url = {https://pubs.usgs.gov/publication/gp619},
  note = {Source identifier: gp619}
}