@misc{indiciae425505a5f4cc,
  title = {Purified protein derivative (PPD).},
  author = {P J Lachmann},
  year = {1988},
  doi = {10.1007/bf02053842},
  url = {https://pubmed.ncbi.nlm.nih.gov/3146815/},
  note = {Source identifier: 3146815}
}