TY  - BOOK
AU  - Gradshtein,I.S.
AU  - Boddington,T.
TI  - Direct and converse theorems : the elements of symbolic logic 
U1  - 511.1 GRA  
PY  - 1963///.
CY  - London : 
PB  - Pergamon Press, 
KW  - Axioms
KW  - Logic, Symbolic and mathematical
KW  - Set theory
ER  -