@misc{indiciae81bf4917c262,
  title = {Letter: IPPB: yes or no?},
  author = {G P Sheldon},
  year = {1976},
  doi = {10.1378/chest.69.1.133},
  url = {https://pubmed.ncbi.nlm.nih.gov/1104285/},
  note = {Source identifier: 1104285}
}