@misc{indiciaeca28ba6381ea,
  title = {Results of spirit leveling in Missouri, 1896 to 1914, inclusive},
  author = {Robert Bradford Marshall},
  year = {1915},
  doi = {10.3133/b568},
  url = {https://pubs.usgs.gov/publication/b568},
  note = {Source identifier: b568}
}