TY  - RPRT
TI  - Descriptive studies: what they can and cannot do.
AU  - David A Grimes
AU  - Kenneth F Schulz
PY  - 2002
DO  - 10.1016/s0140-6736(02)07373-7
UR  - https://pubmed.ncbi.nlm.nih.gov/11809274/
ID  - 11809274
ER  -