Introduction to the calculus of variations  
Dacorogna, Bernard, 
 - 3rd Edition 
 - London : | Singapore ; | Hackensack, NJ :  Imperial College Press ; | Distributed by World Scientific,  2014 
 - xii, 311 p. ;  24 cm. 
<br/><br/><label>ISBN: </label>186094499X | 1860945082 (pbk.)