00441nam a2200109Ia 4500008004100000082001900041100001600060245007200076260003800148300002900186500011600215250307b        |||||||| |||| 00| 0 eng d  a515.72bK19.SI  aKato, Tosio  aA short introduction to perturbation theory for linear operatorsb/  aNew York:bSpringer-Verlag,c1982  axiii, 161p. Index, Bibl.  a"Slightly expanded version of chapters 1 & 2 of Tosio Kato 'Perturbation theory for linear operators, 2nd ed.'"