TY  - BOOK
AU  - Lewis H R
TI  - Unsolvable classes of quantificational formulas
SN  - 0-201-04069-7
U1  - 511.3 
PY  - 1979///
CY  - Reading
PB  - Addison-Wisley
KW  - Combinatorial analysis
KW  - Mathematical logic
KW  - Unsolvability
ER  -