TY  - BOOK
AU  - Langer, SK
TI  - Introduction to symbolic logic(an)
SN  - 9780486601649
U1  - 510.6 
PY  - 1967///
CY  - New York
PB  - Dover
KW  - LOGIC
KW  - MATERIAL IMPLICATION
KW  - VARIABLES
N1  - Ref. sec
ER  -