Smolin, Lee. <br/><br/>
Three roads to quantum gravity / 
Lee Smolin. 
 - [S.l.] :  Basic Books,  2001. 
 - 240 p. ;  21 cm. 
<br/><br/><label>ISBN: </label>0465078362 9780465078363 
<br/><br/><label>Dewey Class. No.: </label>530.143