Sacks, Gerald E <br/><br/>
Degrees of unsolvability 
Gerald E. Sacks 
 - 2nd ed 
 - Princeton, N.J  Princeton University Press  1963 
 - ix, 174 p. ; 24 cm. 
<br/><br/> Bibliography: p. 173-174 
<br/><br/><label>ISBN: </label>9780691079417 
<br/><br/><label>ISSN: </label>63009996 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Recursive functions<br/>Unsolvability (Mathematical logic)
<br/><br/><label>Dewey Class. No.: </label>517.5 SAC