@misc{indiciaeee3d86608f66,
  title = {Map of land modified by man in the Ambridge 7 1/2-minute Quadrangle, Allegheny County and vicinity, Pennsylvania},
  author = {J. S. Pomeroy},
  year = {1974},
  doi = {10.3133/ofr7474},
  url = {https://pubs.usgs.gov/publication/ofr7474},
  note = {Source identifier: ofr7474}
}