Sagan, Hans. <br/><br/>
Introduction to the calculus of variations   
by Hans Sagan 
 - New York  McGraw-Hill  1969 
 - xvi, 449p. 
 - International Series in Pure and Applied Mathematics .
<br/><br/><label>LCCN: </label>63-13614 
<br/><br/><label>Dewey Class. No.: </label>515.64  / N69