@misc{indiciaeb30d174dca8e,
  title = {Preliminary Bouguer gravity map of eastern Maine and adjacent Canada},
  author = {Dennis S. Hodge and Wallace A. Bothner and Robert W. Simpson},
  year = {1980},
  doi = {10.3133/ofr80618},
  url = {https://pubs.usgs.gov/publication/ofr80618},
  note = {Source identifier: ofr80618}
}