HYDON, Peter E. <br/><br/>
Symmetry methods for differential Equations : A Bigginer's Guide. 

 - Cambridge.  Cambridge University press.  2000 
 - xi, 213p. 
<br/><br/><label>ISBN: </label>0-521-49703-5 
<br/><br/><label>Dewey Class. No.: </label>530.15'535