KATO, Tosio <br/><br/>
A Short Introduction to Perturbation Theory for Linear Operators 

 - New York.  Springer-Verlag, US  1982 
 - xiii,161p; 
<br/><br/><label>ISBN: </label>3540906665 
<br/><br/><label>Dewey Class. No.: </label>515.7246