@misc{indiciae51f1edfadcab,
  title = {An empirical assessment of refraction error in leveling as a function of survey order and environment},
  author = {Robert O. Castle and Robert K. Mark and Roger H. Shaw},
  year = {1994},
  doi = {10.3133/b2114},
  url = {https://pubs.usgs.gov/publication/b2114},
  note = {Source identifier: b2114}
}