@misc{indiciaec72207364c73,
  title = {Classifying clinical severity to help solve problems of stage migration in nonconcurrent comparisons of lung cancer therapy.},
  author = {D G Pfister and C K Wells and C K Chan and A R Feinstein},
  year = {1990},
  url = {https://pubmed.ncbi.nlm.nih.gov/2369742/},
  note = {Source identifier: 2369742}
}