@misc{indiciae976e16489fa4,
  title = {Tracking change over time},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {2011},
  doi = {10.3133/gip133},
  url = {https://pubs.usgs.gov/publication/gip133},
  note = {Source identifier: gip133}
}