00357    a2200133   4500020001500000082001900015100001700034245003500051260005100086300002200137650001600159650003500175650001300210  a0521098939  a515.35374bCOP  aCopson, E.T.  aPartial differential equations  aNew DelhibS. Chand & Company Ltd.c1976g1989  avii, 280p.c22cm.  aMathematics  aPartial differential equations  aAnalysis