@misc{indiciaed5081bbe6ec9,
  title = {Results of spirit leveling in Illinois, 1896 to 1908, inclusive},
  author = {Samuel Stinson Gannett and David Henry Baldwin},
  year = {1910},
  doi = {10.3133/b421},
  url = {https://pubs.usgs.gov/publication/b421},
  note = {Source identifier: b421}
}