TY  - BOOK
AU  - Sacks,Gerald E.
TI  - Degrees of unsolvability
T2  - Annals of mathematics studies
U1  - 517.5 
PY  - 1966///
CY  - Princeton, NJ
PB  - Princeton Univ. Press
N1  - Literaturverz. S. 173 - [175]
UR  - http://www.gbv.de/dms/hbz/toc/ht001035299.pdf
ER  -