Second order elliptic equations and elliptic systems  
Chen, Yazhe, 
 - Providence, R.I. :  American Mathematical Society,  1998 
 - xiii, 246 p. ;  26 cm. 
 - Translations of mathematical monographs,  v. 174 .
<br/><br/><label>ISBN: </label>0821809709 (alk. paper)