Heinonen, Juha ; Kilpeläinen, Tero ; Martio, O. <br/><br/>
Nonlinear potential theory of degenerate elliptic equations 
/ by Juha  Heinonen et.al 
 - New york:  Dover publications,  1993.xi, 404p. 
<br/><br/><label>ISBN: </label>0486450503 
<br/><br/><label>Dewey Class. No.: </label>515.96  / HEI/N