@misc{indiciae292f45c80162,
  title = {Two ancillary devices for use with a piped-gas system.},
  author = {J S Crawford},
  year = {1973},
  doi = {10.1093/bja/45.7.763},
  url = {https://pubmed.ncbi.nlm.nih.gov/4730173/},
  note = {Source identifier: 4730173}
}