Rektorys, R N Karel <br/><br/>
Variational methods in mathematics, science and engineering 

 - 2nd ed. 
 - Dordrecht  D Reidel Publishing  1980 
 - 511 p. 
<br/><br/><label>ISBN: </label> DFL65 
<br/><br/><label>Dewey Class. No.: </label>515.7 R449V