@misc{indiciae69680b9643b0,
  title = {Combined mobility system for the blind.},
  author = {J D Armstrong},
  year = {1969},
  doi = {10.1038/2221301a0},
  url = {https://pubmed.ncbi.nlm.nih.gov/4182838/},
  note = {Source identifier: 4182838}
}