TY  - BOOK
AU  - Simpson,R L .
TI  - Essentials of symbolic logic / 
SN  - 0415018706
U1  - 511.3 
PY  - 1987///
CY  - London : 
PB  - Routledge , 
KW  - LOGIC, SYMBOLIC AND MATHEMATICAL
N1  - Includes index
ER  -