@misc{indiciaeacb92a4fac51,
  title = {Geology and petrology of the Greenville quadrangle, Piscataquis and Somerset Counties, Maine},
  author = {Gilbert H. Espenshade and Eugene L. Boudette},
  year = {1967},
  doi = {10.3133/b1241f},
  url = {https://pubs.usgs.gov/publication/b1241F},
  note = {Source identifier: b1241F}
}