TY  - RPRT
TI  - Developing improved observational methods for evaluating therapeutic effectiveness.
AU  - R I Horwitz
AU  - C M Viscoli
AU  - J D Clemens
AU  - R T Sadock
PY  - 1990
DO  - 10.1016/0002-9343(90)90182-d
UR  - https://pubmed.ncbi.nlm.nih.gov/1978566/
ID  - 1978566
ER  -