Friedrichs Kurt O <br/><br/>
Perturbation of spectra in hibert space 

 -  1965 
 - p.  cm. 
 - Lectures in Applied Mathematics; 3 .
<br/><br/><label>Standard No.: </label>22141 
<br/><br/><label>Source: </label> Textual 
<br/><br/><label>Dewey Class. No.: </label>B313N08, K51