@misc{indiciae7b9f50c860f1,
  title = {Map of land modified by man in part of the Freeport 7 1/2-minute Quadrangle, Allegheny County and vicinity, Pennsylvania},
  author = {W.E. Davies},
  year = {1974},
  doi = {10.3133/ofr74290},
  url = {https://pubs.usgs.gov/publication/ofr74290},
  note = {Source identifier: ofr74290}
}