@misc{indiciae525181637036,
  title = {A simple accurate plane and incline indicator.},
  author = {A L L BELL and J ZWANGER},
  year = {1952},
  doi = {10.1148/58.2.259},
  url = {https://pubmed.ncbi.nlm.nih.gov/14892255/},
  note = {Source identifier: 14892255}
}