TY  - BOOK
AU  - Sacks,Gerald E.
TI  - Degrees of unsolvability
U1  - 517.5 
PY  - 1966///
CY  - Princeton, N.J.
PB  - Thea250 University Press
KW  - Recursive functions
KW  - Unsolvability (Mathematical logic)
N1  - Bibliography: p. 173-175
ER  -