@misc{indiciae8baf2b17ab28,
  title = {Table of differences of altitude to nearest foot for angles from 1 minute to 2 degrees and for distances under 1 mile},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1891},
  doi = {10.3133/70047701},
  url = {https://pubs.usgs.gov/publication/70047701},
  note = {Source identifier: 70047701}
}