@misc{indiciaee5c897454744,
  title = {Principal facts for gravity profiles at Orrington and Waterville, Maine},
  author = {Robert W. Simpson and Paul LaPierre},
  year = {1978},
  doi = {10.3133/ofr78849},
  url = {https://pubs.usgs.gov/publication/ofr78849},
  note = {Source identifier: ofr78849}
}