TY  - RPRT
TI  - Sample size for studying intermediate endpoints within intervention trails or observational studies.
AU  - L S Freedman
AU  - A Schatzkin
PY  - 1992
DO  - 10.1093/oxfordjournals.aje.a116581
UR  - https://pubmed.ncbi.nlm.nih.gov/1462974/
ID  - 1462974
ER  -