00382nam a2200133 a 450000500170000008200160001710000230003324500490005626000350010530000280014049000370016863000200020563000230022520251203091009.0  a512.55bDOU  aDouglas, Ronald G.  aBanach algebra techniques in operator theory  aNew YorkbAcademic pressc1972  axvi, 212p.b22 cm.cHB.  aPure and applied mathematicsd49  aOperator theory  aAlgebra techniques