Garey, Michael R. and Johnson, David S.  <br/><br/>
Compute and Intractability  : a guide to the theory of NP-completness 
Garey, Michael R. and Johnson, David S.  
 -   W.H. Freeman  1979 
<br/><br/><label>Dewey Class. No.: </label>511.352  / N79 GAR.J