@misc{indiciaed3de05b7938e,
  title = {Sputum retention.},
  author = {P Stangel},
  year = {1989},
  doi = {10.1378/chest.95.4.939b},
  url = {https://pubmed.ncbi.nlm.nih.gov/2924639/},
  note = {Source identifier: 2924639}
}