Ovsiannikov, L. V. <br/><br/>
Group analysis of differential equations   

 - New York  Academic Press  1982 
 - xvi, 416p. Index 
<br/><br/> "Translation from the Russian ed. by W. F. Ames".   
<br/><br/><label>Dewey Class. No.: </label>515.35  / Ov96.GA