@misc{indiciae4944380ab86e,
  title = {Letter: Samples for hepatitis B antigen testing.},
  author = {C R Madeley and G E Urquhart and S McMichael and N R Grist},
  year = {1974},
  doi = {10.1136/bmj.4.5942.465},
  url = {https://pubmed.ncbi.nlm.nih.gov/4425923/},
  note = {Source identifier: 4425923}
}