Non-linear operators and the calculus of variations   
ed. by J.P. Gossez, [et al] 
 - Berlin  Springer Verlag  1976 
 - 237p. 
 - Lecture Notes in Mathematics  V.543 .
<br/><br/><label>ISBN: </label>3540078673 
<br/><br/><label>Dewey Class. No.: </label>515.73  / N76;2