@misc{indiciaea649f0a48270,
  title = {The selective salvation of Zeiss Ni 1 levelings},
  author = {Robert O. Castle and Thomas D. Gilmore},
  year = {1994},
  doi = {10.3133/ofr94698},
  url = {https://pubs.usgs.gov/publication/ofr94698},
  note = {Source identifier: ofr94698}
}