00304nam a2200121Ia 4500082002000000100002500020245002200045260004400067300001600111490004500127500000500172700000500177  a515.72bL865.ST  aLorch, Edgar Raymond  aSpectral theoryb  aNew YorkbOxford University Pressc1962  a157p. Index  aUniversity texts in mathematical science  a  a