TY  - RPRT
TI  - Differing results for efficacy--sampling bias or purposive sampling?
AU  - Francesco Mercorio
PY  - 2003
DO  - 10.1016/s0015-0282(03)02196-4
UR  - https://pubmed.ncbi.nlm.nih.gov/14607605/
ID  - 14607605
ER  -