@misc{indiciae29bb65ffbffe,
  title = {Modern instruments for surveying and mapping},
  author = {G.D. Whitmore and M.M. Thompson and J. L. Speert},
  year = {1959},
  doi = {10.1126/science.130.3382.1059},
  url = {https://pubs.usgs.gov/publication/70010947},
  note = {Source identifier: 70010947}
}