@misc{indiciaeb61ddeafb0de,
  title = {Map of land modified by man in part of the Valencia 7 1/2-minute Quadrangle, Allegheny County and vicinity, Pennsylvania},
  author = {John S. Pomeroy},
  year = {1974},
  doi = {10.3133/ofr74117},
  url = {https://pubs.usgs.gov/publication/ofr74117},
  note = {Source identifier: ofr74117}
}