@misc{indiciae90d519852e53,
  title = {Skin testing for tuberculosis. Antigen and observer variability.},
  author = {F J Erdtmann and K E Dixon and C H Llewellyn},
  year = {1974},
  url = {https://pubmed.ncbi.nlm.nih.gov/4594690/},
  note = {Source identifier: 4594690}
}