@misc{indiciaec709e2c0bb0a,
  title = {Economic geology of the Beaver quadrangle, Pennsylvania (southern Beaver and northwestern Allegheny Counties)},
  author = {Lester Hood Woolsey},
  year = {1906},
  doi = {10.3133/b286},
  url = {https://pubs.usgs.gov/publication/b286},
  note = {Source identifier: b286}
}