@misc{indiciae170027c6cce3,
  title = {National Center tour guide},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1979},
  doi = {10.3133/70039073},
  url = {https://pubs.usgs.gov/publication/70039073},
  note = {Source identifier: 70039073}
}