@misc{indiciaed1ca93ce2856,
  title = {Aeromagnetic map of part of the Marblehead South quadrangle, Essex and Suffolk Counties, Massachusetts},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1970},
  doi = {10.3133/gp710},
  url = {https://pubs.usgs.gov/publication/gp710},
  note = {Source identifier: gp710}
}