00370nam a2200133 a 450000500170000002000150001708200170003210000180004924500600006726000340012730000250016149000280018670000220021420251203110319.0  a3540411607  a515.353bGIL  aGilbarg,David  aElliptic partial differential equations of second order  aBerlinbSpringer-Verlagc2001  axiii,515p.c24cm.PB.  aClassics in mathematics  aTrudinger, Neil S