TY  - RPRT
TI  - Classifying clinical severity to help solve problems of stage migration in nonconcurrent comparisons of lung cancer therapy.
AU  - D G Pfister
AU  - C K Wells
AU  - C K Chan
AU  - A R Feinstein
PY  - 1990
UR  - https://pubmed.ncbi.nlm.nih.gov/2369742/
ID  - 2369742
ER  -