TY  - BOOK
AU  - Walker,Alexander Muir
TI  - Observation and inference : an introduction to the methods of epidemiology
SN  - 0917227077 
AV  - RA652.4 .W35 
PY  - 1991///
CY  - Chestnut Hill
PB  - Epidemiology Resources Inc.
KW  - Epidemiology
KW  - Epidemiologic Methods
ER  -