Applications of Lie Groups to Differential Equations/ 
Olver,Peter J. 
 - 2nd 
 - New York:  Springer,  1993. 
 - 513 
<br/><br/><label>ISBN: </label>0387940073 
<br/><br/><label>Dewey Class. No.: </label>515.35  / OLV/A