@misc{indiciae081901e67382,
  title = {Prothrombin time proficiency testing: a robust grading method.},
  author = {Y Han and W B Lawson and W J Dodds and C E Lawrence},
  year = {1985},
  url = {https://pubmed.ncbi.nlm.nih.gov/4089800/},
  note = {Source identifier: 4089800}
}