Lewis, Harry R. and Papadimitriou, Christos H. <br/><br/>
Elements of the theory of computation 

 - 2nd ed. 
 -  Prentice-Hall of India, New Delhi  2002 
 - 361 
<br/><br/><label>ISBN: </label>9788120322332 
<br/><br/><label>Dewey Class. No.: </label>Column-23