Ovsiannikov, L.V <br/><br/>
Group analysis of differential equations 
L.V. Ovsiannikov 
 - New York  Academic Press  1982 
 - xvi  416 
<br/><br/><label>ISBN: </label>0125316801 
<br/><br/><label>Dewey Class. No.: </label>10.01  / OVSI