@misc{indiciaefaf066be503a,
  title = {Lithology, thickness, and extent of hydrogeologic units underlying the East Portland area, Oregon},
  author = {S.V. Hartford and W. D. McFarland},
  year = {1989},
  doi = {10.3133/wri884110},
  url = {https://pubs.usgs.gov/publication/wri884110},
  note = {Source identifier: wri884110}
}