@misc{indiciaeaf56e98e1ea4,
  title = {Slit-beam ruler.},
  author = {M A Callahan and S J Kimura},
  year = {1976},
  doi = {10.1016/0002-9394(76)90372-x},
  url = {https://pubmed.ncbi.nlm.nih.gov/937439/},
  note = {Source identifier: 937439}
}