@misc{indiciae9a0216f0534b,
  title = {Letter: Pneumococcal antigen in sputum.},
  author = {J Verhoef and D M Jones},
  year = {1974},
  doi = {10.1016/s0140-6736(74)90544-3},
  url = {https://pubmed.ncbi.nlm.nih.gov/4132846/},
  note = {Source identifier: 4132846}
}