TY  - RPRT
TI  - Field epidemiology: methodological constraints and limitations in the developing world.
AU  - E E Ekanem
PY  - 1985
DO  - 10.1016/s0033-3506(85)80125-6
UR  - https://pubmed.ncbi.nlm.nih.gov/3991874/
ID  - 3991874
ER  -