@misc{indiciae5f56423a0f53,
  title = {Letter: Expiratory bacterial filters.},
  author = {J Norman},
  year = {1976},
  doi = {10.1016/s0140-6736(76)92884-1},
  url = {https://pubmed.ncbi.nlm.nih.gov/59221/},
  note = {Source identifier: 59221}
}