00297nam a2200121Ia 4500082002100000100001700021245004000038260003600078300000900114490004200123500000500165700000500170  a515.72bSo722.LO  aSoule, J. L.  aLinear operators in Hilbert spaceb  aNew YorkbGordon & Breachc1968  a40p.  aNotes on Mathematics and applications  a  a