TY  - BOOK
AU  - Gilbarg David
AU  -  Trudinger Neil S
TI  - Elliptic partial differential equations of second order
T2  - Grundlehren der mathematischen wissenschaften; 224p
U1  - B334,1,2, L7 
PY  - 1977///
CY  - Berlin
PB  - Springer- Verlag        
ER  -