Lavrentev, M A <br/><br/>
Variational methods : for boundary value problems for systems of elliptic equations 

 - New York  Dover  1989 
 - 153p.  
<br/><br/> Includes bibliographical references and index 
<br/><br/><label>ISBN: </label>486661709 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Boundary value problems<br/>Calculus -- Variations<br/>Conformal mappings