TY  - RPRT
TI  - How to do a simple epidemiological study. II. Practice.
AU  - T J Bowker
PY  - 1996
DO  - 10.1016/s0167-5273(96)02801-x
UR  - https://pubmed.ncbi.nlm.nih.gov/9024906/
ID  - 9024906
ER  -