@misc{indiciae5afbf030f61d,
  title = {Speaking tubes for office use.},
  author = {M Armstrong and P L Efros},
  year = {1993},
  doi = {10.1177/019459989310800625},
  url = {https://pubmed.ncbi.nlm.nih.gov/8516020/},
  note = {Source identifier: 8516020}
}